How to break hymen with penis without pain
your query is just as common as any other's.
when your penis is fully erect follow this method:
a. pull up the foreskin of your penis fully till it is behind the glans.
b. then pour a tiny bit of lubricating oil (not machine oil) over the glans area.
(the lubricating oil here is specially manufactured for penile and vulval applying. you can get it from any online site here in america/canada)
c. massage your penis for a few strokes.
now slowly insert your penis into your girlfriend's (or wife's) virgin vulva. give the penetration a few pushes very gently. her hymen would break but she won't feel the pain. but remember, you must indulge your girl to a strong foreplay of at least 15 minutes before inserting your fully erect penis into her vulva.