McCockblock 

Someone who inadvertently or purposely cockblocks themselves. And others. As often as possible. Attached as a last name for emphasis.

Dayum, I am such a McCockblock.

Oh, yeah I was so gonna get with that guy, but they don't call me Jessica McCockblock for no reason.

McCockblock by Cathy with a K April 21, 2007

captain McCockblock 

a master cockblocker, a fonzie type that is the reason you're still masturbating every night

Gee thanks captain McCockblock! There goes my last chance of experiencing paid for sex.

captain McCockblock by captain McDoucher August 5, 2011