Think back to your single days, fellas.  Being a wingman to your friends meant that you would abide by a certain code.  You and your friends would go out to the bar and some things were just expected.  Before I go on...

TheHusBlog Definition Pause : Wingman Duties (Ladies, if you are reading this please know that I do not approve of these duties but they are/were a fact of life for many men)

• Validate My Story, Bro : If one of your buddies is chatting up a nice young lady and starts to embellish a story, or hell, even make one up, it is your job to not only go along with the story but to also add to it, with maximum realism.  If your buddy is talking about how he won the Olympic silver medal in the 100 meter dash in 2004, it is your job to describe the weather in Athens that day.
• Block The Enemies, Dude : When trying to gain a phone number, or even a potential hook up with a lady your buddy is going to encounter barriers.  It could be the target's best girlfriend-"We came together we leave together", her gay friend-"Come on girl, I thought we were just going to dance tonight", or another suitor-"Girl, what do you say we get out of here".  It is your job to chat up the girlfriend, talk about musicals with the gay friend, or challenge the other suitor to a game of pool.  After all, your buddy would do the same thing for you if your situations were reversed.
• Get Lost, Hommie : As things begin to go well for your buddy, you might have to find a way to bow out, gracefully and unassumingly so that your hommie and his new girl can have some time alone.  This sometimes comes at a great cost, maybe he was your ride, maybe you have to give up on her friend, or maybe you have to keep chatting up her friend at another location so your buddy can move forward with his girl.  In any case you have to go!