I think many people like myself who are anxious and introverted do not press enough. I know a few lost opportunities with girls who I really had a connection with and there was ample opportunity for me to sexually escalate but I didn't. Those are the times I really regret.

One secret I have learned is that if you are introverted like me and don't want to directly go in for the kiss, you need to at least touch her sexually. This means start touching her with your fingers along her shoulders, arms, neck or thighs. Her reaction to these touches will give you ample evidence to gauge whether you are able to take things further. I employ this technique, and even if the girl does not want to escalate things it is not awkward afterwards. I know many times when I was younger and with girls who I was really infatuated by, I could have easily done this with but was only thinking of the big kiss or sleeping and this paralyzed me to do anything at all. My advice is start small.Even just touching thighs together and rubbing them slowly is enough to gauge her response. If she immediately pulls away, you know she is not ready. If she leans in then you can escalate, and if she remains neutral and doesn't either retract or her face doesn't show that she is feeling horny, I say move on to a different part of the body but keep escalating because at least she is not stopping you. Remain on the side of aggression rather than passively waiting for a signal from her. There is not one time I regret being too aggressive(I am actually a very passive individual so I am addressing those who are usually passive and anxious like me), but there are many times I regret not trying to escalate enough even though the moment was perfect and I was too much of a pussy.