Drok stood up and took notice of Grok leaking.
"Grok fuck Drok?" Drok asked a little excited
"Yeah." Grok replied starting to stroke his cock a little "Drok decide how Grok fuck."
Drok had to think for a minute. Even before he was a caveman, he didn't know many sex positions. However now he had a hard time remembering any of them.
"If Drok no make mind, Grok know many way to fuck." Grok said
Then it hit Drok like a ton of bricks.
"Grok do cowboy." Drok answered
Grok then nodded and sat down on the floor with his hard cock now at a full 17 inches. As Drok walked over, he could feel his cock twitch out of excitement and leak pre. He then reached to where Grok was sitting and spread his ass as much he could. Despite his new caveman brain, he knows it's gonna hurt. He then lowered himself unto Grok's cock. As the head entered Drok's ass, he found himself moaning loudly. Drok wanted to hold out a bit, but he came as Grok's cock head had fully entered. Most of the yellow cum landed on Grok, who merely rubbed into his chest hair.
"Drok tight." Grok remarked "Drok never have sex before?"
Drok's blush gave Grok his answer.
"Drok no worry. Drok will have plenty while here."
Drok nodded and started to slowly move down Grok's cock, letting out a variety of noises as he did. Not even a quarter of the way down, Drok stops moving down.
"Drok stuck?" Grok asked
"Yeah." Drok answered still blushing
"Many mans get stuck on Grok cock." he said "Once Drok bigger, Drok handle Grok cock better."
Grok then twisted his nipples to get himself to cum again. Drok was caught a little off guard. Not only by how sudden the release was, but also how it felt inside him.
"Grok....cum....warm." Drok said in a haze
The warmth quickly spread throughout Drok's body. He could feel his body growing stronger, but it was just barely noticeable if you were to look at him. Drok then smiled and continued down Grok's cock. The process of Drok getting stuck and Grok cumming in him would happen a few more times until Drok had taken in Grok's full length. At that point, Drok had grown small pecs, a four pack abs and some decent definition to his arms and legs. His spine start to curve slightly while some of the length he had in his legs moved into his arms.
"Drok body look good. Drok look more like man." Grok said
"Drok love new muscles." Drok said as he flexed his arm "Drok want have body like Grok!"
"Grok happy do."
Grok suddenly started to pound Drok's ass. Drok then wrapped his arms and legs around Grok. As soon as his cock touched Grok's abs, Drok let out another load which was a darker yellow and a thicker consistency than before. Grok came more than the last few times soon after. His body grew to about half of what Grok's was.
"Drok almost done." Grok said
Drok then responded with a kiss which caused both of them to cum at the same time. Drok's four pack quickly turned into a six pack after taking in the latest load. Drok would take in another five loads for his body to be around the same as Grok's . Drok then stood up, flexed his arms and smelled one of his armpits, liking the smell. Grok then stood up. While Drok was a little shorter than Grok, they were both happy with the results. The two of them could be brothers.
"What Drok do caveman?" Drok asked