what am i meant to do in this situation?

ive been spending time at a friend’s house for about a week and every now and then her boyfriend will stay the night. we all share a room (they sleep in her bed and i sleep on a couch in her room) and sometimes when they wake up if they think im asleep they’ll fuck around a bit. afaik it’s just hand shit since my friend will talk about the stuff they do together and they haven’t done any penetrative sex
this has only really happened twice and the first time they woke me up during so i just went back to sleep and didn’t mention it. this morning though i woke up way before then and i was laying down reading when they woke up and started fucking around. i told them it was awake when i realized what was happening

anyways i just wanna know what the appropriate thing to do in this situation is? i suppose i could talk to my friend and ask what she’d prefer but then she might worry about me being awake the whole time and i don’t want to ruin their fun as awkward as it is
if i could id move to another room and let them finish up in private but that’s not really an option since my friend still lives with her parents and friends are meant to stay in her room

any advice?
no matter what im gonna have to talk to my friend about this while she’s driving me home