Late last night, I was masturbating in my room. I thought it was safe, and that everyone was asleep, but I was wrong. My evil seventy five year old grandfather who doesn't know what privacy is, walked in on me pumping myself with a makeshift dildo (I'm fifteen by the way).What do I do, shrug it off and act like nothing happened? Confront him? Also, what things can I do to make sure no one walks in on me? (I don't have a lock on my door)
Keep an eye on him. If he's acting like it never happened, don't worry. If he is acting very insecurely about it, you might have to confront him. I can't help you with that part.
As for making sure you don't get caught again, try to figure out a way to masturbate while not drowning out the noise outside, such as leaving the door open a crack or masturbating slower. Try to do it under a blanket if you really can't do that, so if someone walks in, you can pretend to be asleep.
Hope I helped! ^^