DEAR ABBY: I'm a single mother of two amazing boys, 16 and 12. While my older son has been private about coming into puberty, my younger son is very open about it, and we have had many conversations about it. Abby, I'll be honest. The subject makes me uncomfortable.

Last night I walked into my 12-year-old's room and interrupted him pleasuring himself. I was shocked, and I started to laugh because I was embarrassed. I did tell him he needed to be more private about his curiosity, to close the door and have a blanket over himself. But I was laughing when I was talking to him and literally could not stop.

I'm unsure what is the right course of action at this point. Where do I go from here? -- EMBARRASSED MOM

DEAR EMBARRASSED: Masturbation is natural. Every healthy, normal person has done it. It is not depraved, a crime or harmful to one's health.

Your son is now at an age when it is appropriate for Mom to knock before entering his room out of respect for his privacy. So: Apologize to your son for laughing. Explain that it was because you were embarrassed.

If your children's father is in the picture (or another male relative), a man-to-man talk about this could be helpful. If there isn't one, consult your sons' pediatrician for suggestions on how to discuss sexuality with both of your boys. If you haven't already done so, the time has arrived.

DEAR ABBY: My brother, three sisters and their husbands and children and I go to our parents' house for holiday dinners. My youngest sister's husband refuses to go because he doesn't get along with our family. (He also does not get along with his own family.)

Before my youngest sister leaves, she insists on taking a plate of food home for her husband who was "unable to be there." I feel if he doesn't want to be with our family, he shouldn't be allowed to have takeout. Our mother is 82, and it upsets her that he doesn't want to be there. What do you think? -- RESENTFUL

DEAR RESENTFUL: If your brother-in-law can't get along with the family, he is doing everyone a favor by not attending those family dinners. Because your mother finds his absence upsetting, it is up to her to put her foot down and tell your sister she doesn't want food taken to him. Until she does, food deliveries will continue.

DEAR ABBY: I, too, am disgusted with people who answer their cellphones wherever and whenever.

I was at a funeral last week where this twit answered her cellphone while viewing the deceased in his casket. She was literally kneeling beside the casket when her phone rang, and she carried on a conversation with the caller for a full three minutes. I timed it!

I know some people may think this is funny or no big deal. I suggest that those who feel that way should learn manners. Unless you're a doctor or some other emergency caretaker, there is no reason to take a call while in the company of others. -- MICHAEL IN ROCHESTER, N.Y.

DEAR MICHAEL: I agree. When attending a funeral or a memorial, cellphones should be turned off out of respect not only for the deceased, but for the others around you.

DEAR ABBY: I would like to respond to "Solitary Woman in Ottawa, Canada" (March 5), the expectant mom who asked how she could raise her child to enjoy "periods of quiet, reflective fun by himself."

I have two children, ages 7 and 1. Like "Solitary," I also enjoy time to myself, whether reading, writing or going for a hike.

When my son was born, I felt it was important to give him confidence and the ability to be self-sufficient. Therefore, we have him help us with chores like grocery shopping and encourage him to make healthy, responsible choices. When he was 2 and stopped taking naps, we told him he had to have "quiet time" and that reading to himself was one of the options.

As a result, our son is self-motivated, an avid reader and writer, and has an intellectual curiosity most adults don't have. He is teaching himself cursive writing and is interested in learning a foreign language.

We live in the Colorado Rockies, and getting rid of our TV set was one of the best things our family has ever done. Instead of tuning each other out, we enjoy conversation, creating and sharing our days together. I have never been happier as a father or husband.

I am concerned for people who are afraid of silence. I suspect it's a sign of sensory bombardment. The human mind needs moments of clarity brought on by reflection. -- DAD WHO GETS IT

DEAR DAD: Thank you for your letter. I received many thoughtful comments from people who identify strongly with "Solitary's" point of view:

DEAR ABBY: Your advice to "Solitary Woman" was good, but did not start soon enough. She should provide stimulating crib and playpen toys to teach her son at an early age that he can control some aspects of his environment. Having this ability is the key to enjoying solitude.

When my daughter was 7 weeks old, I attached a mobile fashioned from a white wire coat hanger and rainbow-hued origami cranes to her bassinet. I wiggled it and watched her smile at the moving colored birds. When the movement stopped, she became frustrated and began to whimper and kick and flail her arms. The paper birds moved again. She lay still and watched them. When they stopped the second time, she didn't whimper but just moved herself in the bassinet. She had learned she could control her environment.

As a toddler she could leave her playmates and pursue solitary activities in the quiet of her own room. I am convinced that her bassinet experience was the basis for learning to be happy by herself and with herself. -- SMART MAMA IN EL CAJON, CALIF.

DEAR ABBY: According to a journalist and mother who published a book on the topic, when an infant cries, wait a few minutes and listen before reaching out. This gives the baby time to learn how he feels with himself, and to deal with it emotionally. After five minutes or so, if the baby has a real need, then you can reach for him. Doing it too quickly prevents this crucial process of learning to be with oneself. -- ANOTHER SOLITARY CANADIAN

DEAR ABBY: As a teacher (now retired), I was always interested in personality types and how they affect learning and interaction with others. One way of dividing personality types is into introverts and extroverts. Introverts get their energy from quiet time alone; extroverts get energy from being with other people and sensory activities.

This is an inborn trait that cannot really be taught, and there are varying degrees of the introvert/extrovert characteristic along a continuum. Wise parents will learn their child's personality traits and tailor their parenting to help him/her have the best learning situations possible. -- MARY IN TEXAS

DEAR ABBY: I took care of my grandmother until her death a few years ago, and now my mother is very sick. I feel angry because I'm only 23, and it seems all I have ever done is take care of sick people. I sit at the hospital sometimes just fuming.

Mom was a smoker and now she has cancer. I keep thinking if she hadn't smoked, she wouldn't be in this fix, and neither would I. I always visit her and try to do everything she asks of me, and yet I think I'm starting to hate her. I dread going to the hospital, sitting there and waiting for test results, etc. What kind of daughter has feelings like this? -- WORST DAUGHTER ON EARTH

DEAR DAUGHTER: Please stop beating yourself up. Your feelings are normal. You have a right to be angry that your mother is sick. At 23, you have had an unusual amount of responsibility thrust upon you for someone your age. That her disease has taken over your life is also a reason to be angry.

However, please stop blaming her for her illness. Right now, you need each other. And nonsmokers get cancer, too. The American Cancer Society has support groups where family members can safely share their feelings. Please check them out.

DEAR ABBY: I'm 43 and went back to school the nontraditional way. I will graduate soon with my master of human services degree. I will be the first person in my immediate family to have a degree.

My best friend thinks I'm foolish because I posed for graduation photos and ordered a class ring. She said I am too old to be having graduation pictures and a ring. I was thrilled to have them, but now I'm wondering if I really am being foolish. Am I trying to recapture the "would have/could have/should have" years? -- ED IN LOUISIANA

DEAR ED: Shame on your friend for raining on your parade. With a best friend like this, you should never forget to bring an umbrella.

You're celebrating the fact that as a nontraditional student you have earned your master's degree. That's a laudable accomplishment and deserves to be celebrated in any way you would like. Please accept my sincere congratulations, graduate!

DEAR ABBY: I love to read. I have kept every book I have read, so I probably have close to 600 books in my library, which is actually a small room, overflowing with books and nothing else.

Why do you think I can't let go of them? I lend them out to only a select few, and I always make sure they are returned. I could do lovely things with this room if my books weren't in the way, but I can't seem to part with them. -- BOOKWORM IN NEW YORK

DEAR BOOKWORM: It's probably because your books have become an extension of yourself. Because you would like to do something else with the space they occupy, sort through them and keep only the most precious ones. If there are titles you would like to read again one day, do as many others are doing -- read them on an e-reader.