Well, I guess I have the fortunate experience of not being concerned about this. I jack with my friends regularly anyway and my former roomie. Although before my roomie became comfortable enough to do it in front of me and be nude and all etc., there were many times when we were first living together we walked in on each other. One of the most memorable times was late Saturday/ early Sunday morning, like at 2am. He was suppose to be spending the weekend with his girlfriend so I had the place all to myself.
Me being always horny and a nudist, I put down a towel, popped in some porn in the living room and stripped. With a huge bottle of lotion and my pocket pussy I went to town.
Now his girlfriend lived about 20-30 minutes away (drive time) and his car was in the shop...yet he showed up anyway, bursting the door open, out of breath, piss drunk, sweaty and bleeding from his head. Since I left my clothes in my room and there wasn't anything in the living room to cover up with close by, not even a pillow or a blanket, I just sat there frozen with my dick still in the pocket pussy.
He looked at me and didn't say anything at first, he just went straight to the kitchen for a bottled water. (small apt, kitchen was part of the living room) After he grabbed the water he flopped himself down on the couch and just said, "oh, you're jackin' off?." (I was sitting on the floor). He then just proceeded to tell me what happened. How he ran back to our apt from his gf's house...I'm still sitting there naked, hard with the pocket pussy on my dick, I at least paused the movie.
But apparently they had a huge fight and she threw his cell phone at his head, hence the huge cut and all the blood. He had been drinking earlier and she didn't like him drinking, why she was hitting him and threw the phone at him. Long story short, we carried on the conversation for a good 30-40 minutes and aside from occasionally glancing at my cock, he didn't really have a problem with it and didn't do anything either. It was like any other normal day. I did at least hand him the box of tissues to wipe the blood off his head. When he was done talking though he did say, "Now I have to jack off." But he decided to do that in his room...So once he left to his room, I started the movie back up and just carried on, hoping that he would join me instead of doing it in his room, but that's another story.