Pronounced (Fell-lay-hay-low)
Portmanteau of fellatio and halo.

To receive oral sex while playing Halo or any video game. Particularly an online first person shooter.
Tom: are you alright betty?
Betty: yeah tom i gagged when you flinched
Tom: sorry i got hit with a grenade while you gave me fellahalo
by Thomas Coleman December 8, 2007
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