Dailies | Zac Efron Explains ‘Sack Tapping’ in a Very Awkward Talk Show Moment (Video)

The “Neighbors” star was really good or just decent at scrotum punching, depending on who you ask

These days, talk show interviews with celebrities are meticulously planned, with talking points prepared for the actor and host ahead of time… which can get awkward when one side is more prepared than the other.

Take Zac Efron‘s Friday night appearance on Graham Norton's popular UK chat show. Efron was there with his co-star Seth Rogen to promote their film “Neighbors” (or, in England, “Bad Neighbors”) and shoot the breeze over a few drinks.

See video: Watch Zac Efron Get His Shirt Torn Off at the MTV Movie Awards

They began talking about fraternities, since Zac plays the president of a Greek life organization in the film, but because Efron didn't go to college, Norton had to stretch a bit and ask Efron about his propensity for playing “fraternity-esque sorts of games.”

“You were very good at sack tap?” Norton inquired.

Efron was a bit embarrassed, but explained the game — it's quite complicated — but then took a bit of an issue with Norton's characterization.

See video‘Workaholics’ Vet Seth Rogen and Zac Efron as Potential Cubicle Mates

“I wasn't good at it, I don't know what you mean by that,” he protested. “I avoided it at all cost.”

“That's what the forms tell me,” Norton responded. “That you were super good at it.”

The big question now is who is doing research for “The Graham Norton Show.”

Watch the video above; this particular segments starts at 14:20.