When I was 17, I emigrated to North America to join my father. My mother and siblings came 6 months later. For that 6 months I lived in a boarding house, sharing a room with my father. I slept in a single bed, and there was a small space between the bed and the wall.
Every night, after my father fell asleep, I would maneuver myself so I was leaning against the wall, with my cock pointing down between the bed and the wall, and I would ejaculate onto the floor or the wall.
The landlady never said anything, although there must have been some noticeable stains. It may be that she changed the sheets without moving the bed.
Why I didn't use a tissue, or even toilet paper, I have no idea, but to this day I feel a sense of embarrassment that I could be so careless. At the time, I was so horny, I just didn't care.
Perhaps if I knew others did similar things, my embarrassment about "leaving my mark" would go away.