We all know and we all call Gokudera by his nickname, which is "Gokkun", no?
But take a look at what 'Gokkun' actually means:
http://en.wikipedia.org/wiki/Gokkun.
Thanks to someone on dA for pointing it out. orz;;
ETA: Amano - sensei sure is creative. Tsuna = Tuna, Basil = a type of herb, Gokudera = PORN?! D| But then again, i bet she wouldn't know that people would start calling Gokudera ''Gokkun''.