Sometime female cats can get ‘stimulated’ by scratching them by their tail on their back. If you ever had a queen in heat you see that this releives some of her ‘sexual’ tention.
Other then that, or I guess if you wandered towards their nauty feline bits if you are into those types of things, I would say no. that reaction you describe sounds like their ‘kitten mode reflex’.
Your scratching is like the preening their moma cat did to them when they were kittens, this was also associated with them feeding, so their mouth waters and they drool sometimes.
To go further, kitty sex usually involved the male bitting the female hard, on the scruff. When the tom cat is done and withdraws his ‘willy’ it has a barb that ‘rips’ the female, causing a good amount of pain down there, and also stimulates ovulation. The Tom cat hangs on to her for all he has during this withdrawl, because if she managed to get ‘free’ from him at this time she will most likely attack him due to that pain. Ususally he can hang onto her till the pain goes down and it is safe to descruff her.