Bryan thought long about this. Did he really want to change that much? The smell of the caveman musk he was emanating overrode his good judgement and he asked for the Heavy Brow Beer, Cave Cock Cider, and Body Hair Heineken all in one drink.
The bartender laughed, "ah, the Caveman Cocktail...coming up!"
He handed the drink to Bryan. He warily eyed it, but thought it would be interesting to try. He drank it all in one big gulp.
Immediately, he began to feel very hot as prickly hairs sprang up out of his skin. The texture of his skin became a bit harder too. While this was happening, he felt his cock start to grow, and he wasn't even aroused!
Finally, he began to get a bad headache. Holding his head in his hands, he began to feel his brow beetle outwards. It was the strangest sensation. He began to feel his urges grow more primal as it happened. Looking up in the bar mirror, he saw his eyebrows grow together over his unibrow. He still looked quite handsome, but with his new cock, tufts of body hair, and new facial structure, Bryan felt very aroused.
"I can still think like me". "Me talk like caveman though", he said in a deepening voice.
"Rawr, do you mind if I go jerk off?" Bryan asked the bartender. His new urges were too much to take. The bartender said, "sure, go to the bathroom and splooge all you want to, stud"
Bryan headed to the bathroom, feeling his new primal self. This was going to be weird, but fun.