I've got a PC who has the Extra Attack class feature, and he has polearm master. He is under the impression that every turn, he gets 4 attacks. Two regular attacks and two attacks with the "butt" of his glaive.
Am I wrong in saying that he only gets three because the butt attack is his one and only bonus action per turn? Also, should he be applying his strength modifier to the butt attack? It doesn't seem to be particularly clear in the book and I'm a very inexperienced DM.