This fusion is done by placing the hand on the nameks chest and then is then is absorbed into the nameks chest and then they are fused
Piccolo + Nail = Piccolo (Piccolo is the base and it looks exactly like him)
Piccolo + Kami = Kamiccolo (Actually it makes Piccolo but this is what Goku called him when he first saw the fusion)
This is done by doin' a cool dance, they turn out in a cool fusion clothing, this only last for 30 min. The positions and movements have to be just right or else you end up mutated.
Goten + Trunks = Gotenks
Goku + Vegeta = Gogeta
Goku + Vegeta = fat Gogeta (This happened because of a mistake in the dance)
When the two warriors wear the Potara Earrings on opposite ears, and then they immediately get pulled together in a fusion. This fusions result is different from the others because their voice, clothes, and looks combine, and they cannot unfuse(because it's supposed to be permenant). Characters that fuse:
Vegeta + Goku = Vegetto (They manage to unfuse when they were absorbed by Buu)
Other Characters that fuse:
Artificial 17 + Android 17 = Super Android 17