Do this in a dugout or on a football field, no problem.  Do it to a random woman on the street and you could be arrested!

A serial “Butt Slapper” is on the loose in Colorado.  Cops are asking people to help identify him.

What’s a serial “butt slapper”? Well, it appears a guy is riding an e-bike up behind women in the area and smacking them on the back side and then driving away.

Several incidents have been reported so far.  Someone got a shot of him on his e-bike, but you can’t see his face. 

And authorities do NOT think this is funny, it’s actually assault and if caught, the culprit will be arrested!

Read more and check out some photos by CLICKING HERE/Denver 7.com