Mario's timing is perfect as he walks in the room, "Stupid vending machine wouldn't take my money. I'm so fucking hungry damm..." His words are drowned out by Adam moaning in pleasure. Mario turns to look at his naked roommate standing in the middle of the room beating off. "What the F?" Suddenly Adam jerks and semen comes flying across the room and right into Mario's face! It's a huge load that covers Mario's eyes before it starts flowing down. He opens his mouth to shout an exclamation, but the next blast makes a direct hit and cuts off whatever he was going to say.
Blinded by Adam's cum, Mario is unable to see Adam as he starts to grow. His body surges in size as his muscles expand all over. The growth is especially fast in his cock and balls where Adam had been so generous with the powder. His balls are filling up with cum almost as fast as he's pumping it out. Adam is loving the feeling of watching the room seemingly shrink around him, feeling the carpet move under his expanding feet. As he cums, he enjoys hitting Mario and makes an effort to keep his aim as close as possible. Mario is swallowing Adam's spunk as fast as he can, enjoying the taste. He is able to tear off his shirt which was fortunately old and fairly worn. Some of the cum is hitting him in the chest, and Mario rubs it around his exposed torso. He puts one hand down his pants to rub his boner and in between blasts from Adam, undoes his fly and lets his dick out.
Adam eventually runs out of steam as his last few pumps aren't able to reach Mario. He lets out a long breath as his massive orgasm ends. Now that Mario isn't getting hit anymore, he wipes the cum from his eyes so he can see again. He looks up to see the new Adam.