The boys around where I live always seem to act strangely around their dates friends, no matter if its a party, or a meal. Here are a few simple rules for you to learn.
1) Do not ignore the friends! Even if you hate them/they hate you/ or are enemies(trust me-this happens). Some girls have a rule-'mates before Dates' so if you are rude to the 'mates', you will be left behind. If you dont like the friends, just a simple 'Hi, how are you?' will do. Just be civil to them!
2)No serious kissing in front of people. You know the kind I mean.....not only can it embarrass your date, it can also make the friends feel like they dont want to be there.
3) Do NOT flirt with the friends. That will most likely get you slapped!
4)Offer to get the drinks- this works at parties, and at dinner. Offer to pay for the food. Even if they dont let you pay, it will put you in your dates good books, and her friends will like you more.
Thats pretty much it from me on this topic...