My boyfriend dry humped me. he was wearing shorts and underwear but i was naked. his shorts were wet from either me or precum, if they were wet from precum could that cause pregnancy? my period was due september 8th?

Can do preg. test: Sperm do not swim through clothing in real life, so keeping the clothes on is good contraception. For example, wearing jeans with a tight button fly that are really tough to unbutton, and a tight waist to stop hands from slipping through, is good contraception. Of course, a sure way to prevent pregnancy is to never be alone with a boyfriend (safer to be in a cafe, public library, or with family).