Ok so this one is from a few years ago, it's quite harmless but I think a few people will be screaming at me.
Anyway, it was Friday and I came home from work, I didn't see my sister in the apartment but heard the shower so I assumed she was in it (since we live together), she was going to take Sophie to mum's before coming back to get ready to go out.
It had been a long busy day and I had been sweating so I stripped off and put a robe on ready to jump in the shower when my sister had finished.
I put the radio on in my room as I got undressed and started to relax, I heard a door slam shut and came out of my room, Laura's door was now shut and the bathroom door was still shut but I couldn't hear the shower so I assumed she had finished.
I undone the tie on my robe and went into the bathroom dropping the robe off my shoulders as I entered and threw it to one side closing the door behind me, I'm standing there starkers and I notice that my brother is also starkers drying his legs, he looks up and gets an instant hard-on (way to go bro! ha), now if this had happened these days I would probably grab the closest thing I could and start throwing things at him, but back then, and god only knows why, I just walked passed him saying 'close the door when your done' and got in the shower, the cubicle is clear glass so offers no concealment from someone else in the room.
I didn't notice him leave but when I had finished he was in the living room fully dressed watching tv, when he saw me (in my robe this time) he went bright red and couldn't quite get the words he was looking for so I just told him to lock the door next time.
We haven't spoken about it but when ever he's close and I say I need a shower he immediately blushes so I know he remembers..!
It almost caused his girlfriend to leave him when it was a hot day and I said I could use a shower, not thinking about winding him up, but she got the wrong idea when he blushed, I didn't quite tell her the full story just saying he had walked in on me in the shower, seemed to do the trick.!