Hi Chakburthi,
When people engage in sex, their chakras open up and they become much more receptive to prana, both from the universe and from the person they are with. This is one of the advanced aspects of tantra yoga which is not mentioned much in the tantric lessons on this website. The tantra lessons on this website deal mostly with the cultivation of pre-orgasmic sex and other aspects of tantra.
During advanced tantric sex, flows of energy begin to happen between and around the couple who are engaged in lovemaking and these flows have a powerful effect on the purification of the subtle body.
The degree to which the transmission of prana will happen depends on the level of purification of the people involved. So it does not really matter if someone seems spiritually inclined or not.
That is beautiful that you had the opportunity to be in the company of Francis Lucille. The advantage of being in the company of a spiritual teacher is that you will gradually take on the energetic resonance of that teacher, as you discovered. So if they are vibrating at a very high frequency, you will also take on that high frequency. The more purified a teacher is, the greater the physical distance over which their radiance will effect other people who are with them.
Christi