Behind the Bed
I used to be a floor layer, carpets mostly. Few years ago we did a bedroom where the tenant was out and left us a key.
When we shifted the bed out, we found a large amount of condoms behind the headboard as well as clearly stained undergarments at the foot of the bed.
My mate flicked one of the undies with his foot at me and it landed clean onto the back of my head. Story credit: Reddit / Axceon