similar to the cockblock, a godblock is the loss of a sexual action(s) because omnipotent reasoning by the other partner. This can be due to finding god or becoming closer to god, and believing that god disproves of that sexual act.
My girlfriend and i where having sex until she realized that god does not approve of sex until marriage. She immediately stopped having sex with me, a classic godblock.
A "God Block" is when you meet a girl and things are going well, until she brings up god, after which the conversation completely falls apart. Effectively playing the traditional cock block role of the fat friend.
Dude this girl was awesome; we had chemistry, she was hot, and then out of nowhere I got God Blocked. I mean seriously who asks a guy what his favorite hymn is?