Well for participation´s sake, here we go:

tangerine slice
http://images.google.com.br/images?hl=pt-BR&q=tangerine+slice&btnG=Pesquisar+imagens&gbv=2&aq=f&oq=

tangerine wedge
http://images.google.com.br/images?gbv=2&hl=pt-BR&sa=1&q=tangerine+wedge&aq=f&oq=

http://pt.wikipedia.org/wiki/Gomo_(cartografia)
Your friend was right...if he was talking about a globe, baloon, parachute...
At least, for the time being.

Good to know some others names to tangerine (in the southern Brazil region) 
A tangerina (Citrus reticulata), também mandarina, vergamota,bergamota ou mexerica

Tangerine sections.

tangerine segments.
http://images.google.com.br/images?hl=pt-BR&lr=lang_en&um=1&sa=1&q=tangerine+segment&aq=f&oq=

http://www.lebloncachaca.com/cachaca-recipes/muddled/tangerine-honey-caipirinha-recipe/

The Tangerine Honey Caipirinha
Leblon Cachaça
 
2 1/2 oz. Leblon Cachaça
2 slices of fresh tangerine
2 1/2 oz. Tangerine juice
1 tbsp Honey
Glass-Rocks
Muddle tangerine, honey and sugar in a shaker. Add Leblon Cachaça, tangerine juice and plenty of ice. Shake vigorously and pour into a rocks glass. Garnish with a slice of tangerine.

Come bakc to us, if you dooon´t are tipsye alreadyy and slurrring yooor words, afterrr this studdyee.

PP.