Some women find stimulation of the cervix by penis as uncomfortable or painful, others report it to be key to orgasm. The cervix may be confused with the deepest point of the vagina, above and below the cervix, respectively making it possible for there to be indirect and/or simultaneous stimulation between them. During arousal, the vagina lengthens rapidly to an average of about 10 centimetres, but can continue to lengthen in response to pressure. The walls of the vagina are composed of soft elastic folds of mucous membrane skin which stretch or contract (with support from pelvic muscles) to the size of the penis. With proper arousal, the vagina stretches or contracts to accommodate virtually any size penis, from small to large.