Sharing beds

Let me start by saying me and my mom and dad dont always sleep in the same bed every night( one night she might sleep in hers and the next she'll sleep in mine) and that's only because our female dog had puppies and we kept 3 and my rooms the most puppy proof for night time. But what I'm asking is would if they had sex in there bed and then I slept in there bed with no pants on one night because it was really hot and I couldn't go in my room to get shorts or I would have woke the puppies up. Could I have got anything from sleeping with no pants on in the same spot they had sex? Or if I slept in my brothers bed with no pants on and he jerked off could I get anything? And by get anything I mean std-sti wise like hpv, herpes, ect