My favorite technique is to use my king-size foam pillow. I stuff the pillow under the pillow case with soft foam to form breasts, then lay 2 rectangular foam strips approximately 4 by 12 inches under the case at the open end. This forms the vagina. I then use socks, tied off above and below the newly formed breasts to create the shape and size of the upper body that I want. I use just one or maybe 2 socks tied off to create the shape of the waist, buttocks and vagina. This creates the perfect fantasy women for me.
I then squirt KY into 1 or 2 condoms that I place on my penis. I'm now ready to have fun. I insert my penis between the 2 pieces of foam (vagina) and begin to have sex. I may also place my penis between the top foam and the pillow case, depending on the amount of friction or slipperiness I need. Sex can be had in almost any position, missionary, cowgirl, doggie, whatever. Using the foam and sock technique, I can create almost any female body I want. I can stuff large amounts of foam to create large breasts and/or a large or small bubble butt. I've masturbated for many years and found this the most satisfying.