Question: do gohan and trunks fuse?
Answer: In Dragon Ball Xenoverse, during the fight with Super Buu, Goten and Trunks perform the fusion dance and fuse to become Gotenks. In the GT Saga (Part 2), Super Saiyan 4 Goku and Vegeta fuse into Super Saiyan 4 Gogeta during the fight with Omega Shenron.