Smack your hands against your body repeatedly, mainly the torso to chest area, and continue to smack hands on body and say "hambooooniiinngggg" in Rigby's voice from Regular Show.
Rigby: HAMBONINGGGG
Mordecai: No...
Rigby: HAMBONING WILL SAVE YOUR LIFE ONE DAY!!!! It'll be like "what! you tried to mug me?"
*proceeds to hambone for 20 seconds*
Mordecai: NO! We're not doing that, okay!? Okay!?
Rigby: Fine...