A noggin is an imaginative word, it could be a dirty word or it could be nogginly gurrd. You can call it to freinds, family and even turtles. Either way there not going to know what you are on about, however they normally retaliate and call you something back.
Shabba"Hey turtle"... Turtle says "mmpppfff"... Shabba says "you wiped any noggins lately", the turtle then bites your 4th toe.