I'd say it is common, if you say that -usual porn does not do it for me as much as it used to-, you got bored of it and want something more. I'd say that is normal. My experience was getting bored of usual porn, then switching into more believable stuff with amateurs and kinda average looking girls, and then as time went on i started looking up kinkier porn, because I've seen the usual stuff plenty of times and it didnt do it for me as well.

I also felt the urge to do something in the direction of what you're describing, however being the guy I am, I can't do it :p anonymous or not I am too shy haha.

I think an important question would be if it's been a long time since you had sex, if at all? If it indeed has been a long time, then that would also be a reason why it's kinda evolved from watching porn into wanting to interact with girls this way.