There are three type of fusion, fusion dance, namekian fusion and porterra earring fusion.

Fusion dance, is the hardest to perform, because if one of the fusers is the slightest bit out of sync, then the fusion outcome could result in really fat bodies , really skinny bodies... etc. When doing the fusion dance, both must recite, FU-SION-HAAAA. if done correctly, the fusers will combine into a person that is half of each. The fusion only stays for 30 minutes, then you must do it again

Porterra earrings, are ancient earrings handed out by the kais to fuse two people for eternity. each partner must attach one of the earrings to a opposite ear. and they fuse.

Namekian fusion, can only be performed by two nameks. first, both must agree to fuse. then one places there hand on the others lower ribs, and they are fused into one being. often, the person who places his hand on the ribs, is the same person on the outside, but develop attributes, that the other had.