No! There is nothing wrong with male masturbation!
It is a perfectly normal healthy thing done by 98% of men (the other two percent are liars.)
I masturbate once or twice a day. Usually it consists of manual stimulation of my penis. Fingers around the guy and a regular back and forth (if standing) or up and down motion (if lying down). I don't normally require any visual assistance but certainly visuals will generate the desire to masturbate.