Similar to a cockblock but the victim obviously isn't getting any real action.
*On the phone*
John: Yo Dennis! The boys and I are gonna come pick you up! Time to hit the clubs!!!
Dennis: Man, I would but I gotta study right now. Can you come pick me up in like 15 minutes?
John:........... am I handblocking you right now?
John: (hangs up to tell the boys.)