A term rapidly becoming mainstream (in the south east of England) to describe a young (usually immature) male who is obsessed with anal sex to the point that others suspect him of being homosexual. Such people often have a rather large collection of questionable hats which only adds to others' suspicions.
"I can't believe that all he wanted to do was stick it in my arse. He must be a right el gweiro!!"
"Any 'straight' man who likes bum fun more than cunny love MUST be an el gweiro"