Cam girls often do this and this is a vastly consumed porn. This is absolutely not uncommon for a lot of porn viewers as there a lot of porn clips of porn female ladies pleasuring themselves through a dildo or vibrator or even through their fingers. However the very act of masturbing or jerking off is also a fetish of a lot of people. When one masturbates he or she often watches the porn of his or her fetish, and it may be morally questionable hence this is often kept in secrecy. In real life, you often do it alone by yourself because it is an act of basically fucking yourself-it is supposed to be personal, something intimate to yourself. The very act of masturbation is not only and merely lewd in itself but is also almost a sacred act.