Maximus or probe are the two lubes everyone I know uses. But I hope you've done some research and know what you're doing, since there is a much greater risk of both disease and injury with anal sex. Straight people (i'm assuming you're straight) often don't realize that there is a lot of preparation work involved with this.

You should try butter.

Dude, get an education. Even a virgin like me knows that butter is a really bad idea!