well its called circumsizion for one.. and I believe its very painful if you dont get it on birth. It prolly helps for her just like a dildo is'nt usually smooth but I really doubt its gonna make a noticeable difference.
A smart man once said "Its not the size of the wave, its the motion of the ocean."
Oh and you can always take "Sinrex" or "Extenze", yes they actually work lol
http://www.enlargementsolutions.com/penis-enlargement-pills
It might help ..but I dont know how much of help it might be..why dont you consult a sexologist man???