with my boyfriend!?

My boyfriend has been trying to get me to try for years and although I have nothing against it, its just not something I have been very interested in. Im afraid it will feel like you have to take a big pooh and just uncomfortable. It sorta gross' me out... exit only sort of deal. However I have decided to give it a try for his sake tonight since its valentines. He is really sweet about it and isnt forcing me or anything, I told him i would try it when im ready and he really respects that decision. Do you have any advice? does it hurt? eeeek