Brit Speak: "Top Yourself"

[Steve]

I came across this article in the 'Telegraph', and am somewhat baffled
by it.

http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2005/09/20/nteach20.xml&sSheet=/news/2005/09/20/ixhome.html

"Sharon Jenkins, 35, said that her son had been asked to stand up in
class and describe his hobbies, but when he had proved too bashful to
do so, his French teacher ridiculed him. "She told him, 'I don't like
nobodies. Go and top yourself'," Mrs Jenkins said."

. . . . . . . . . . . . . . .

Could someone explain to me "Go and top yourself"?

Personally, I would be more concerned by the teacher saying 'I don't
like nobodies'.

Steve/bboyminn