Few tips on masturbation.
Do not masturbate with dry hand. lubricate it.
Do not stop breathing while masturbating.
Keep your perineum( muscle between anus and base of the scrotum) relaxed. Do not over visualize/ Do not masturbate when excessively excited. Do not hurry, take enough time.empty your bladder before m/b
You can strain your wrist and arm if you do it enough and repeat the same movement but just work out and do computer stretch and you should be fine
myth of going blind has a origin
Semen in the eye can cause an infection and if left untreated can make you blind. so no semen in the eye okay
scar tissue
you can form scar tissue if your to rough to often
Hi there is nothing wrong with you masturbating (hand job as you put it) and there is nothing wrong with the size of your Manhood Take care .........Bob