kitty g-spot?

So I have a weird question about one of my boys, Donnie. He's a neutered 9 month old cat with a very unique personality, which is great. He's not always very fond of ear scratches but will start purring like a jet engine when the area on his back in front of his tail is scratched, he flips over, purrs and pulls himself along the floor in what must be some sort if kitty ecstasy. I don't always rub his tummy because he doesn't always like it, but I've found if I rub right near his penis he'll arch his back and flex his paws. I was doing it for awhile yesterday while watching tv, and all of a sudden he started to make a very strange sound. It almost sounded like a sound he makes when Bobbie is being particularly vicious in one os his attacks. BUT, his eyes were closed, his back legs were almost touching his head, and he was purring. I can't figure it out, is it a good sound, bad sound, should I not do that? I don't know, I've had cats all my life but I have never seen or heard of a cat doing this when scratched like that!!!!!
Thoughts, advice?

Ohhhhhhhhhhhh yeah ms polly has her's and and when i pet her there she flops and bites (gentle love bites) my arm as i rub it!! :eek: :eek: :eek: :eek: :eek: LMAO she is daddys baby girl she never ever leaves my side lol
hootch

My Siamese likes to have his whole spine scratched. I start near his middle and go to his tail. He arches his back up. Not too good a position since his butt is up in the air. Just funny.

I also massage his back all over. He loves it and will lay flat when I do it. I use long strokes and his skin is so limber it really moves up and down. Kitty massages, he would pay big bucks if he had money. LOL

He has tried to rub on my leg on top of the covers like a mating stance but I stop him. Naughty kitty. Don't want to encourage that behavior when company is here. best to stop it at first notice. And he has been neutered so go figure.

My cat Storm loves me to spank his back end near his tail. He also loves me to spank the sides. He goes crazy and will roll on his back and act goofy. He'll even meow for more.:) Sky loves me to scratch the same area and he'll also meow for more. I think these are kitty erogenous zones.;)

LOL, well I'm not too much into turning my kitties on, just my hubby. And hubby doesn't like it either so I don't do it. Can we say jealousy. LOL

I would be satisfied to give them catnip but they don't care for it. :rolleyes: