Re: How do you...
Well, I'm pretty sure ALL parents realize sooner or later realize that their sons masturbate... As for avoiding the visual proof, you should probably do it when taking a shower, after going to the bathroom, etc., etc. Get creative with it. Has this ever actually happened before, where your mother barges in on you or knocks on your door while you're masturbating? If so, you should probably ask for some privacy. Just tell here "Hey, I'm 13, and I think I deserve more privacy than what you're giving me." Everyone in my dad's house is like that - even the step-siblings, not knockin' like my room is their living room - so I just gave up masturbating in there... It's not like she's ALWAYS watching you, right?