If you like it, you should put a ring on it -- you definitely shouldn't do this.

This guy posted a video -- on Valentine's Day, no less -- of him duping his girlfriend into thinking he was going to pop the question.

Yeah, totally uncool, right? In those few seconds when he was on bended knee, this woman had visions of picking her bridesmaids, shoving cake into her future hubby's mouth, dancing with her dad, throwing the bouquet and just about any other wedding cliche you can imagine.

Seriously, this guy is a stone cold jerk. The woman should have dumped him on the spot. Better yet, she should come up with a plan where she leads him on by making him think he's going to get some sex only to deprive him and then kick him to the curb.

Or, at the very least, she should've made his tea...and then thrown it in his face.