My ATF (who I have seen 50+ times over 5 or 6 years introduced me to a (very attractive) girl friend who is staying with her.  My ATF later asked me if I want to try her GF (including greek).  I did not know what to say.  

As long as she is the one who suggested it, it's probably alright.  However if you are the one who raised the idea, then all bets are off.  More and more I see the same girl, they become more and more possessive.  I can definitely sense jealousy when they know I've seen someone else.  One girl even ran off the names of all the other girls I reviewed since I last saw her. LOL  Another girl specifically asked that I not see certain friends of hers anymore even though I had seen them before with an implicit warning that if I don't listen, she will no longer see me.

A HOT, wild, and crzay greek threesome!

When we ask if you will fuck our girlfriends it isn't a trick question.

I don't think you have to worry about jealousies or resentments lol.

If she offered and then gets mad after, then you need to find a new ATF,  lol!

Did it occur to you that maybe her hot new friend is new to the hobby ?  She may be encouraging you to spend some time with her to help her ease into things since you are very well known to her.

For a provider the ask a good client to "break in" a new provider with someone that she knows is safe.  Lucky are the gentlemen invited

We see whomever we want to see, and as many as we like. If you need some kind of approval from your ATF to see another provider, you need to get a new ATF. Why even have an ATF? I had an ATF once. I dumped her as soon as she became possessive. I already have a woman busting my balls at home so I don't need another one.

who will let you do custom T-shirts and caps/hats.  

as long as she picks up your kids from daycare and pays half the mortgage.

See them together!! I am best friends with a provider and I have seen her regulars with her or solo. If the provider is levelheaded enough she will be just fine with it. See her and then go back to your ATF.