He doesn't reallyt, it's just a joke that because Ein gets alot of male stripper like costumes i.e. Halloween 2013, Casual Vol.2, Christmas 2014 etc. oh and he likes mesh vests.
Also Hayate and Ein are the same person but completely different in personality, Hayate is calm and collected but Ein is rowdy and brash in DOA2 instead of asking questions he mostly just pummeled in peoples faces xD