May I recommend any of Diana Richardson’s books if you are interested in reading about Tantric sex.

As for the handshake, or any other touch between people, it is mostly a cultural thing. If you were raised in a society that taught you that a specific touch is sexual, you will most probably experience it as such. I grew up in a society in which the handshake was not considered to be sexual, and so, as a general rule, I don’t see it as sexual.

Cheers,

Maya