There will be something you like about your body, start with that. Do you have pretty hair, or lovely skin, sexy feet, great boobs, a smashing smile? Whatever it is start there. As @AverageGuy says, do something nice for yourself that makes you feel good. I also like that response too btw!
How amazing are our bodies, do you get pleasure from masturbating, maybe, how does that feel? Isn’t amazing how the pleasure works? That is you being totally sexual, not caring what you look like. That’s you, your body, that’s what you can do and what you deserve. Try that more often maybe, and really feel it, what you like.
Then you can say what works for you when you have a partner. Ask what works for them. That’s radiating confidence because it’s a memory (even if you don’t feel it) and will help you have a good time. You can say no. You are not there to be grateful. You’re there to have fun.
For me it was accepting my body was mine, as worthy of respect and good treatment as the rest of me. I exfoliated and moisturised, perfumed it, even though no one else would see. I bought decent undies that flattered, and wore them. For me. I basically treated myself like a L’Oréal ad, because I AM worth it, and so are you.
And when DP came along, and I was surprised he was interested because, you know, I’m not totally perfectly confident, I also just paid him the compliment of believing him. He said that to him I was voluptuous and soft and smelt amazing. I believed him. He got really hard when we kissed. I believed that. He told me I was gorgeous and sexy and sensual and he’d enjoyed himself hugely, I believed that too. And also when he told me he was nervous, and worried I wouldn’t fancy him, and I said I wanted him and he was a phenomenally good fuck, he believed me.
Other people are not totally confident, we all have things we would change but we are all worthy of love, and respect, and fun and lust. Don’t waste time and headspace on the arseholes who don’t share that viewpoint.
DP, who is very wise, says if a guy is attracted, you’ve applied your judgment/standards and he’s not an arsehole (thus far) and has the luck to be in your bed, he knows you’re large and it doesn’t matter. He thinks you’re sexy. So BELIEVE HIM!