As a joke, he chose "Other" and asked for a big white horn between his legs. He wasn't taking it very seriously, so he was surprised when what looked like a big white elephant tusk ripped through his clothing and jutted out from between his legs where his cock and balls used to be.
"Talk about horny!!!"
He found that touching it was even more erotic than touching what had been there before, and though he could no longer cum, he had the desire to use his new horn to joust roughly. The harder he slammed it into things, the hornier and madder it made him. Soon all of his surroundings were ashambles, and he was in a mindless state of horniness that drove him to continue stabbing his horn into whatever he could.
That's when -