What position one feel is most comfortable is all individual.
Some people like you like to sit with their feet crossed, some like to lie on their back (on the floor, couch, bed etc.) and some people like me, like to just sit in a comfortable chair, where I naturally can relax my back and keep it straight. And just place my feet on the floor, and to be relaxed so I can focus the best way I can.
Sometimes, I sit on the toilet, or the floor myself, and even sit on my bed with the feet crossed. It is all individual.
Some people even like to stand on their feet with their spine straight.
Though, if you sit with your feet crossed, the energies may get stuck in your feet and cause uncomfortable and annoying pain or feelings in the feet. This will be released if you direct the energies from the feet up in the base and up the spine and out the crown. Or running, jogging (exercise).
HAIL SATAN!