Oral Sex, as far as sexual stimulation is concerned is no different to Vaginal Sex, only with the mouth taking the place of the vagina. Therefore, any masturbator which involves the insertion of the penis could be considered an Oral (blow-job) masturbator (one of the FleshLight inserts, as well as other similar items, even includes a mouth design). If you're referring to the many brands of Penis Pumps that claim to increase penis size, but are, in effect, nothing more that masturbators, these have been proven not only to have little or no effect on penis size, but can also cause long term erectile dysfunction, as they can damage the penile blood vessels.