Why does my friend act wierd like this?

My friend acts strange in certain situations. Especially when were around ladys. He talks like he's the worlds greatest. he even changes his voice and has a different laugh. he puts on these "gay" lookin glasses an thinks he looks cool. But his act is really transparent and the ladys often just laugh at him. Its kinda embarrassing to watch. Then after he ask me questions like if he looks fat or stuff like that. But he ain't fat.