This has always been one of my favorite techniques. First I'll get a bowl of water and add some ice (I put the ice in water to help melt the sharp edges). Then as I'm stroking I'll slowly slide an ice cube in my anus with my free hand. The cold sensation in my warm ass is incredible. As I feel it melt I will add another one. Doesn't take long and I'm ready to cum.
I'm like a lot of guys in here...I like the taste of my own cum but once I cum I lose interest. So I came up with kinda of an interesting idea while I was playing with ice and masterbating. Just as I was about to cum I grabbed a small bathroom paper cup (lined with plastic wrap) and shot my load in it. Then I took the cup and put it in the freezer. The next time I was in the mood for a little self-pleasure, I went to the freezer and pulled out my little cum-cube and sucked on it while I masterbated. Or, if you don't want to suck on it, I've also tried it where I slid the cum-cube in my ass which was quite a turn on. Loads of fun.