Faking Orgasms

So I am assuming most people have seen the Seinfeld episode where Elaine tells Jerry that when she was orgasming "the panting, the moaning, the screaming".. "fake, fake, fake, fake".. ANYhow.. my question is... do you fake? How often? And if you do have you ever told your significant other? I've faked before, and never told. It didn't seem right.. why fake it if you are going to tell him? Let him think that he is an all-star in bed and get it over with- if his next girlfriend won't fake for him- then he can just think you were an easy goer ;)