Goku decided to go looking for Goten. Together they'd have a much better chance of survival. Closing his eyes and sensing, he managed to get a direction where Goten was. Completely south.

Goku gulped as he realized that this involved heading down... past the magnificent cock and the balls that could rival the sun.

Since he was so small, he could walk on Gohan's body as if it was solid ground. It didn't feel like downhill, but a pretty flat surface, though it rose and sunk with the shape of Gohan's spectacular body.

Hopefully the path he was walking on led down the thigh and avoided the manhood. However Goku was too small to know until it was too late. After all, just heading from the top of the crotch to the balls is a journey that is millions of miles.