I love to masterbate sitting at my computer desk, especially if there is a woman on her webcam, but I have to alternate between stroking and typing, which makes it last longer.
Sometimes, I use short, fast strokes when I am so horny I just want to blow.
The feeling when I know I am about to cum and I can feel it travelling up my cock is amazing, on more than one occasion I have seen stars!
Hearing a woman cum on the telephone whilst wanking is another good way to get off, hearing her moan and get closer to orgasming. That usually triggers me off and we come together.
I sometimes fantasise about my female work colleagues, especially the ones who are married and I tell them that I want to fuck them very hard and nasty...lol