I have had my Grey 3 years, she is about 3 years 6 months old, she has been doing this a while now, and always when she is on my arm.
I do not think any thing is wrong just more curious than anything esle.
I have no idea, but I have a baby grey myself, not yet home from the pet store, and I am very curious about this, so I will ask around.
If nothing is wrong, perhaps it is just something that has been accidentally reinforced? However, I want to ask other people who have greys to see if anyone else has heard of it and can offer a better explanation.
Yeah She loves you very much. Does she regurgitate for you? Goober tries on occasion and I'm trying my best to keep from reinforcing it.
You may want to avoid petting her back, wings, or body especially her lower back as those will encourage mating behaviors. In the wild, only a bird's mate will spend long periods of time preening them, especially preening the body. Stick to petting just her head until she's able to 'calm down' a bit. Also, since she's displaying mating behaviors, you may want to start her on a calcium supplement since there's the potential for her to lay an egg on you