1. Penis with a bulbous deformed head that is disproportionately larger than the shaft., 2. Used to describe a loud or obnoxious person. Most effective when preceded with a traditional expletive, (i.e. "You fucking Yam-hammer"), 3. An aggressive consensual sexual act that involves a sound beating and/or pummeling.
1. I'd love to yam-hammer that bitch!
2. Seven is a twisted fucking yam-hammer, and someone should whip his ass.