Your 'Jap's eye' is your urethra.
It is not a vein. You shouldn't injection anything in it or any views in your penis cause if you miss you could end up getting an abcess and needing part of or all of your cock chopping off if it is not sorted quick enough.
Also you could do damage to the nerves and loose feeling and sensation in your penis, which would be almost as bad as loosing your penis since you'd no longer get sexual pleasure from the penis being stimulated.
I however think you're trolling considering what you're talking about and your lack of post's.