Akin to housewife's knee, swimmer's ear, footballer's wife, and other such afflictions acquired by engaging in too much of one thing. Not that there's such thing as TOO MUCH sex. But if there were, feeling the pain of the strained, overworked knob would tell you enough is enough! IF there were. Rider's Knob would be your knob's way of saying "I can't take this shit no more, let's just keep it between you and me for a while, no more o' that ol' pussayyyyy." But that's coz your knob is gay! Mine says, "I'm fuckin' wrecked, but I'll play through the pain coz it's worth it!" That's a good knob.
"Can't ride you today, Mrs. McGhee. I've got Rider's Knob."
Milkman to Mrs. McGhee. He certainly missed his gee.
"Can't ride you today, Mrs. Gloria Spot. I've got Rider's Knob."
Milkman to Mrs. Gloria Spot. Certainly missed her G-Spot.
"Can't ride you today, girlfriend. I've got no penis. I mean... emm... I've got Rider's Knob. Yes. That's it."
Joe to his girlfriend. Certainly missed his chance. I'll take that, then.