i haven't had a girlfriend for a while, but i think that sexual alchemy unfolds nearly as much internally as between two people; how conditioned your energy body is has a big effect on your quality of consciousness, and some sexual aspects of this can be addressed without a partner.
when without much contact with women in the past i've wondered what to do with my sex drive. it could probably be suppressed if you really wanted to; at times i would go for a month without stimulating myself, just trying to apply my attention elsewhere. yes, desire can cause suffering - but i would be wrong to leave no room for this part of my physiology and spirituality. so after taking more time to look into the subject (previously i had really only focused on the physical techniques in the taoist approach), i started to see the energetic side of it.
now i don't try to make my sexual energy go dormant, i work on directing it... i'm left feeling a lot more balanced.
but yeah, there's a whole bunch of awesome stuff i'm waiting to try out in my next relationship