I guess I have a very different take on this. To me, Maya has always been a very sexual person. From the moment we meet her, she is quite relaxed about her body, wearing provocative clothes, and being very friendly, if not quite flirty with the MC.I think Maya lost her fear in EP7 so she can't fuck the MC without Josy. Josy made the suggestion in EP6 that she should be there to make Maya feel comfortable.
But Josy said something else to Maya in EP6. She can drink some alcohol beforehand to make her more relaxed. In EP8, she literally pours the whiskey down her throat. But through this, Maya also finds the courage not only to fuck the MC, but also to ask him if and how he decided. "Little kids and drunks always tell the truth" and both are drunk.
She also witnessed in EP8 that Josy is playing with the MC and teasing him. Josy then does the same thing to the two of them at the water park. The girls are talking and Josy will have given Maya some tips.
Josy and Maya don't see each other as competitors and when the MC is not on Jill's path, Josy and Maya actually get their validation so there is nothing to worry about between Jill and the MC.
Her hesitance derives, we eventually discover, from a) being in a relationship with Josy, and b) being a PiV virgin. And despite these factors, she puts up little or no resistance to the MC fingering her quite early in their relationship. She also gets turned on when Quinn forces her to grind the MC in her underwear.
Shortly after this, she tries to go all the way (twice) but can't quite manage it, and let's face it, Daz penises can pretty scary. During this time, she also has a quite uninhibited, intense lesbian session with Josy. And of course, Josy's experience and support helps her to overcome the final hurdle to sex with the MC. Once that psychological barrier is overcome, she is quick to experiment with the MC without Josy's assistance and finds to her delight that she more than enjoys vaginal sex with the MC's scary dick.
So, I'd say her behaviour following that event is, if anything, pretty subdued. As others have noted, after taking that step, it's common for couples to root like rabbits for at least a month or two. In fact my suspension of disbelief is strained to breaking point that this sexy throuple has not yet managed to have a proper threesome - but then that does make for great dramatic tension.
