The sexual relationship with Jill will be as "girlfriend" as possible. I don't have a better english word in mind than "girlfriend" to express myself.
Maybe "girlfriend at 15 years old".
I just hope that she is not a virgin and that, once these "barriers of society" are removed, she will give herself body and soul.
But yes, surely things will start with the calmest possible way. I imagine that's what Jill fans want.
I do not doubt that the first sex scene with her can only occur in the third season.
That, or she'll lose her temper in an hour and things will get out of hand. But if the DPC does that, I hope he does a great job of progression in this little scene, which creates the lust.