Is it because he is bored and not enjoying the sex?

Don't worry, men don't care little detail, just the whole picture

Well, I would need more information to answer your question, BUT. I can tell you two things:

1. At your age, if you "feel fat", you're not. That's just society pressuring you to be thinner than realistically possible. If you don't have stretch marks, that's good -- even if you did, most guys like me like to "kiss them", just to make their ladies feel better. We know you've ruined your bodies for OUR children. And we appreciate it.

2. If Sex takes a long time, this is usually a nice thing for a guy. He is either (1) drunk, (2) in love with your body, (3) both. Most guys will not spend a lot of time "pushing" on a girl they don't find hot. Trust me. I am 35. I've had plenty of one nighters, at times blitzed!

You're best bet is to just be YOU. And don't be afraid to say to your man, "hey, baby, want some more of this? "

Guys don't worry about your body as much as you do. I speak for myself here and most likely many other men as well. Remember this that if the guy is in bed with you, and is in bed with you for the second, third, fourth...what ever number of times, he really likes your body the way it is. You turn him on more then you realize because he keeps coming back for more, right? As far as what you can do for him, ask him if there is anything special that he would like you to do and try and do that.

Don't be too agressive lol. But be confident about yourself. If you're insecure, the guys see it and they think you're going to constantly need reasurance from them all the time. Be happy. Don't show him that you're concerned that he may not like you.

Instead of letting him GET on top of you, stand up and kiss him, walk to the bed (or wherever it is you're planning on doing "it") and push him down. Climb on top of him. Show him you know what you're doing, and despite the fact you think you're "fat", show him you're also happy. It's gonna work. I guarantee it :)

I don't think guys worry about a girl's body as much as we worry about our bodies. Take control, feel confident, men love confident woman. Tie him up, tickle him, play dress up anything to make it fun and always be unpredictable. One of my favorites is body paint. There are many different flavors find out his favorite. Write your name on him and tell him he's yours and let him enjoy you lick it off of him.

I will have to tell you, I have been on weight watchers since January. I have lost almost 40 pounds. It is a long process, but you can do it, and walk for about 30 minutes a day. Get your life back under your control. In bed, you need to step up to the plate. Make it fun, do fun things. Play dress up or something. haha I need to take my own advice on that one. Anyway, if he is the one doing all the work all the time, it's not as fun for him or you for that matter. Once you start losing weight, you will feel good, entergetic and more confident in the bedroom. Turn the lights off, blindfold him--this is a great idea, cause it feels really good for him. Blindfold him and kiss him all over. This is excellent, cause he doesn't know what or where you will be kissing him next. It is very sensual!! I promise. Try it!! I hope this helps you a bit.