Dynamite

A physically large guy meets a woman at a bar, and after a number of drinks, they agree to go back to his place.
As they are making out in the bedroom, ready for the act, he stands up and starts to undress. After he takes his shirt off, he flexes his muscular arms and says, "See there, baby? That's 1000 pounds of Dynamite!"
She begins to drool. The man drops his pants, strikes a bodybuilder's pose, and says, referring to his bulging legs, "See those, baby? That's 1000 pounds of dynamite!" She is aching for action at this point.
Finally, he drops his underpants, and she grabs her purse and runs screaming to the front door.
He catches her before she is able to run out the door, and asks, "Why are you in such a hurry to leave?"
She replies, "With 2000 pounds of dynamite, and such a short fuse, I was afraid you were about to blow!"