Well, size doesn't "matter", but curved cocks are such a delight! 

My ex-bf, he is only about 4 1/2 to 5 inches.  He can sort-of angle or turn himself so that they can hit the g-spot titillatingly.  I must say that i love the sex better.  He make me cum like crazy. 

Most of the womans sensations is in the first 1/3 of her vagina anyway.  And the G spot is typically toward the back of that third on the roof.  It doubles when it hit that sensativity part.

To all the gifted crooked men out there, providing a little communication with your partners, things may definitely be to your advantage.  USE IT WISELY!