the best method, natural stretching, it is called jelqing. don't buy pills, they are lies and only enhance the way sex feels, and nothing els. you penis is sponge tissue, not a mussle, protien will NOT enhance the size of your penis.
if you want tips on stretching your penis naturaly, google in penis enlargerment methods. (PE)
they worked 100% for me, and im 16. grew up to 2 1/2 inches and 1 inch in girth in a matter of months.