Every time me and my boyfriend have sex he does all the work and after we finish he ask if I'm going to ride him and I tell him no so he gets mad and doesn't want to do it sometimes. I am very shy when its comes to having sex so what do I do?
First, only do it if you want to. But do try and be brave - most women really prefer it because you can control depth and movement (and the delicious grind). Plus he can caress and touch you with his hands way more effectively this way, which you will both enjoy. I think you'll be pleasantly surprised!
There are ways to address your demure shyness. Try it under the covers the first time and lie against him (his head should be propped on a pillow or two). This will keep you from being too visible and it is more intimate.
Try reading a sex book or maybe even watching porn with him. You have to start getting over your fears little by little. Take baby steps. Your over 18 and have nothing to worry about anymore, you have a boyfriend, not just some random guy. You should want to please him, not be scared of intimacy.