Awkward conversation about phone sex

Soooo I have a weird problem... My sister, who is 6 years older than me, is in a long distance relationship and they see each other quite rarely. I know she speaks on the phone with him every day, which is normal. But lately they started having phone sex and she puts him on speaker, so I can hear them panting REALLY HARD and REALLY LOUD.

I know it's normal, I can understand the need... BUT it just makes me feel really uncomfortable, I mean it's my sister, I don't wanna hear that 🤮 whenever I hear them, I'm uncomfortable to walk around the house, so I try to stay as far away from her room as possible (which is hard because we don't live in a huge house) 😐 first they were doing it in the evening, when I could've been sleeping, but today they did it in the middle of the afternoon and it was really hard not to hear. I don't know what to do, I don't know how to talk to her about it - she's not very good at taking criticism and whenever I try to tell her to do something differently, she lashes out at me (for example, another day I reminded her to put the dirty dishes in the dishwasher and she started attacking me about stuff I do).

I also feel like I should let her know I can hear them and maybe suggest that she uses ear buds, but I don't know how to start that conversation? Or am I being too dramatic and I should just let it go?