My bf whenever we have sex or do oral, he'll go down on me and and play with my clit n shit and it feels real good don't get me wrong, but like, my legs n shit shake a fair bit and it feels like a lot somehow, IDK what to do cause I feel like that's just how it is and if he keeps going I'll cum or something but idk what to do cause I eventually have to ask him to stop and do other stuff and later he'll go back and it repeats, anyone have an idea why my body does this? And how I can stop it from happening cause I don't want him to stop doing it but I can't stand too long or it gets too much.