When a drunk person is persistently looking at you out of the corner of their eye.
"Boy I could feel John sideballing me all night while I was talking to Bill, he's got to get over it!"
von BRC 6. Oktober 2005
To look out the corner of your eyes at someone so that they "can't tell your looking"
I changed my radiator in the parking lot of the apartment complex. Noone said anything, but alot of people were sideballing.
von Tug33 18. Mai 2011