Tenga FLEX Rocky Black Male Masturbator, The FLEX’s spiral-ribbed casing has created “spinning stimulation”. Cover the air hole at the top of the item during use, and the FLEX will wind and unwind, creating a spiraling movement! Additionally, the FLEX’s malleable casing allows you to squeeze, twist and grip the item to directly change the stimulation to suit your desire!
https://www.youtube.com/watch?v=A0Ttqgx1c_Q