A big-butt childhood friend who met again after 3 years turns into a slut and gets fucked in a pounding cowgirl position

My childhood friend and neighbor Kokoa, who is also a neighbor, have been close since she was little, and they have always been playing together. We are now in middle school and reaching adolescence. He was always making fun of his big butt, which is Kokoa's complex... Kokoa moved out as soon as she graduated from junior high school. Kokoa has returned to this town for the first time in three years. I am confused by the reunion. The plain guy has been completely sophisticated and seducing me by showing off his big butt.