one who pounds his bitches head into the wall/headboard while fucking her.
"I couldn't sleep last night 'cause Gary kept poundin his bitches head into the wall all night. He's such a boomdog".
A pussy or coward. Someone who gets scared easily.
Jake: Oi mate come we go bang those guys...
Damien: Nah allow it they are heeench
Jake: For fucksake dame why are u such a boomdog?