If there is no need, let your body be and do what it does. But if there is need and sexual desire, circulating upwards truly the sexual energy, without years of strong practice and opened systems, will lead to extremes and danger.
If you truly redirected this upwards, your legs would've hurt beyond reason. So what you essentially do is control this energy on a surface level on these things. Be aware how you do these.
You need release, and most probably after it hits the Sacral chakra, your carnal desire may explode (among other desires and genius power of creation) and you won't know how to tamper this off, as masturbation won't satisfy this need. You'll have to practice sexual union days on end and hours on end to just make this energy a little bit more relaxed.
If you imprint the desire and memory of something that cannot realistically happen, this energy hitting upwards won't be satisfied with anything but the fantasy being created, which then is impossible. So focus on the realistic aspects of these.
