This happened two years ago when I went on my vacation.
It was my last full day at the airbnb and the sun was out so i decided to sun bathe naked since it was a nice day and wanted to even out my tan.
I ofcourse forget to put the do not disturb sign on my door and she came in with towels and other stuff into my room.
I saw her staring at me through the sliding glass door and I immediately get turned on. She doesn’t realize yet that I know she’s staring so I start to play with my cock.
Once I’m hard I look directly at her and smile, she starts to blush and smile. She was a bit flustered and embarrassed so I get a towel and wrap myself with it.
I apologize to her and tell her I forgot to put the sign on the door, she giggles and says it’s ok no harm done.