What do i wear under a surf wetsuit?

Nothing is okay, unless you are surfing someplace where you might have t change without a towel or a car to sit in. Board shorts are okay for some people, but if that is too uncomfortable for you, and you choose not to go 'commando' a Speedo or bike shorts are nice, tight fitting alternatives. Whatever you do, don't listen to the guy who said put Vaseline on your wetsuit. Although I don't really think it will harm the neoprene, it will make it virtually unwearable and a slippery mess in no time. Even in the 'old days' (I started surfing in '66) before we had improved neoprene wetsuits, we used tal powder to help slip them on, not petroleum jelly.