Similar to a cock throb, cock twitch, chubbie, or chubster, it's when a man's penis undergoes vasocongestion. It is the swelling of the penis by increased vascular blood flow and a localized increase in blood pressure. Typical causes include sexual arousal, strong emotions, allergic reactions, and dancing too fast. Dick pulses are funny but never talked about and I'm sure a few ladies have seen and appreciated a good dick pulse every now and then.
OMG did you see her legs? I think I just got a dick pulse." or "We're hitting the road to the Coachella Music Festival. I think I just got a dick pulse.