I've slept with a lot of close girl friends, many of which became a serious relationship. NOT THAT I RECOMMEND IT!!!
But, the strange phenomenon was that I wasn't really interested in them as a romantic choice, so I didn't start off coming on to them and thus get pushed into the friend zone. I opted for friend interaction while I spun plates elsewhere, either because they had other boys, or my friends were chasing them and I didn't wanna ****block, or whatever. A big part of this was that kino with these girls was minimal.
Then, if the girl became more drama-free available and I had decided that we had fun and were good company, I'd slide up the kino dramatically out of nowhere for a couple days, then a few days later we'd be ****ing like crazy.
Something about drawn-out, repressed sexual tension makes for some crazy sex.
Also... THIS IS NOT A TECHNIQUE! The few girls this happened with were all very unique situations.
One in high school, there was nothing that weird about fooling around with the girls in your circle of friends. Most kids opt for this cause there aren't a lot of scenes for pick up.
One was a girl I worked on a newspaper with. It wasn't until after I had left the newspaper that I targeted her and started inviting her over and working things. She ended up being a BPD chick and I doubt this woulda worked with other kinds of girls.
One was a nymphomaniac in ****ed up relationship with her boyfriend and he was in some sort of philosophical moral dilemma where he felt guilty about having sex and hadn't screwed her in over a month. So she was hot and bothered. That only lasted a week and ended badly.
One hadn't been in a relationship since she got divorced and her friends were pushing her to date me. She hadn't considered it before because I was friend-zoned, the peer pressure allowed that one to happen. That lasted 2 months before her roommate confessed his undying love to her and they eloped to a different state together.
The last one is my most recent ex. We were roommates for 5 months, though not very close. I went off and travelled for 6 weeks, came back very different and self-empowered and started spending a lot of time with her. A month of this I realized I was really into my roommate, and escalated the kino intensely then made out with her a couple days after that decision. It took her 3 weeks before she would sleep with me, but she was a weird girl, and we ended up in a very dramatic relationship that lasted over a year, way longer than I had anticipated. Incredible sex, though.
So, I don't recommend it, none of these worked out swimmingly, but there's a way to do it with the right initiative and quick follow-through action. They will look at the kino as just very close friendship and lie to themselves about the sexuality despite the tension they feel, so following through with making out with them quickly after has to happen or the window will be missed. All these girls told me they had no idea I was into them until after my tongue was down their throats (paraphrase).
But, save yourself some drama and just go spin some plates.