My ex-wife and I were always very sexually open. We were both bi and I had a thing about watching her while she sucked someones dick. I would get sooo hard when I watched her. I will say though I let her give head to anyone she wanted to if she told me she was going to do it or if she had done it.
I will say, the one time I just watched her get licked by another female and jerked-off, I couldn't believe how I reacted. Now understand, my dick is about 6 inches long when hard. I was able to edge the whole time I watched her. My dick at this point was a maroon color, harder than ever and it was accually 9 inches long. when she saw this, she freaked out. She wanted to ride it so bad but I don't think she totally understood what peaking was yet. I told her she couldn't get on it because it was to sensatave. I had almost came a minate before this just by taking my hand off and releasing my grip, even though I wasn't moving it at that moment. She knelt down infront of me and put her hand on my dick, just staring at it. I shot a load that made me scream like never before. I couldn't beleive how hard my load shot out of my dick. It accually shot over me (I was in the recliner) and onto the wall behind me. My dick has never been that hard after that.