It can be anytime she's in the kitchen in the morning (which is a 3 hour span of time, 8-11 I think) but you probably need to get her to 190 or 200 affection. Not that difficult, as you can get 20 per day if you do all the things.
Once you unlock the ability to grab her ass (which leads to a handjob), you will get a -20 affection drop every time you cum on her face - although that raises her depravity by one point each time you do it.
As for Amelia, once you complete the massage at the massage parlor, you have to go to the store to buy a massage table AND you have to buy her special massage outfit before you can start giving her the much more intimate massages at home.