Throughout my most horny years, I had to share a double bed with a little brother. He was an unplanned addition to the family, seven years younger than me. When I began wanking in the seventh grade he was not even in first grade yet. Much of my energy throughout middle school and high school was spent on making sure that he never knew what I was doing when nature called at night.
When I got back in bed under the warm covers, my boner wouldn't leave me alone. I knew I was going to have to "do it." Laying on my back with a couple of tissues in my left hand, I held the covers up very slightly and started jacking. Tiny little strokes, not enough to shake the bed. Just barely moving my fingertips and trying not to get tense. I was scared of making any motion, scared even to move my feet or get a different grip on my boner.
I was alert to my brother's breathing pattern. If he moved or rolled over or made the slightest noise, the hump in my covers collapsed and I lay there holding my pulsing erection but not making the slightest motion. Gradually he would resume steady breathing. I'd raise the covers again and continue the tiny little jiggles on my horny dick.
Due to the very light stroking that I did, it took me several minutes to get fully primed. Finally I was on the verge of cumming. This was the critical time, the most dangerous moment. What if he woke up right when I was ejaculating? I wouldn't be able to stop. But it never happened. I would get ready for the climax. Would remind myself not to shake, not to jerk, not to flinch when the stuff shot out.
My left hand moved to hold the tissues around the tip of my dick. Sometimes I would count down to the instant of ejaculation: Getting there, getting there! Max sensations! So good, so freakin' good!!! Three! Two! One! Aaah! Cumming! Oh, Hallelujah, CUMMING!
I lay there without moving for a minute or two. Sometimes I went back to sleep with my fingers around my dick and woke up later still holding onto my guilty organ. But usually I got another tissue to wrap around the two cummy ones. Then put my tool back in my underpants and dropped the evidence on the floor until getting up and taking it to the bathroom to drop it in the toilet.
I'm certain my brother never knew what was going on.