What do I do with the semen after masturbation, and I'm in my room.
Wipe it up with a damp wash cloth and then rinse the wash cloth in the bathroom sink. You could wipe it up with a tissue, but it begins to stink after a few days.
Say I don't have those things with me after masturbating, then what?
It isn't that difficult to go and get a wash cloth from the bathroom, dampen it and go back to your room to clean up. If it is in the middle of the night and you don't want to disturb anyone, then just wait until morning. If the semen got on your pajamas or underwear, just take them off, and when you go to the bathroom in the morning rinse them out. If you are washing clothes that day, put them in the wash; otherwise, spread them out to dry so they don't sour before you get them washed. If the semen is on your sheets, then plan on washing them the next day.