Although we're not sure what the custom is in Charlize Theron's native South Africa, there is still a universal code for what's acceptable when it comes to slap and tickle with other guys.
Just ask her beau Stuart Townsend, who stormed out of West Hollywood's Crown Bar on Friday night with the blonde after she got a bit rowdy with a bystander.
The couple, attending an anniversary party, were hitting a bottle of bubbly all evening until one onlooker tells RadarOnline.com that Theron got a little hands-on with a nearby dude.
"She leaned over the table and smacked some other guys ass," an eyewitness tells us.
"Stuart looked pissed, and looked at her and said 'Why did you do that?'"
Clearly she didn't have a satisfactory answer, as our onlooker tells us the couple bickered all evening before heading out.
"They constantly fought the rest of the night together, and ended up leaving the party early in a big huff," said the spy.