so my boyfriends parents are going out of town on Thursday & we've never had the house to ourselves. he's 21 & im 18. we're thinking about taking a romantic bath together & i know at first it'll start off like that but towards to the end i know there will be a lot of rubbing/grinding. i REALLY don't want to get pregnant. & i know at some point i will be on top of him. i'm a virgin but he isn't he respects my reason for me still being a virgin. so i was wondering would i get pregnant if he cums in the water?