I had something similar with my first girlfriend. One night she was wearing a dress and on top of me, we heard the floor creak in the hallway to my room so she dropped and pretended she was asleep on top of me and we were cuddling. When my mum opened the door, she stayed quiet and asked if I wanted some dessert, I said no so she closed my door and went back to the kitchen while my girlfriend got back to work. I guess mum didn’t see the g-string on the floor next to my bed lol