For me anyway. I have a very sensitive area in the front of my vagina (meaning towards the front of my body). It can be reached and stimulated in several ways, but is most responsive to pressure and vigorus rubbing. I've identified this spot as "the G-Spot" as it's stimulation causes spasms and contractions in nearly every muscle in my body. Though different from the clitoral orgasms which are generally more intense, a vaginal "G-Spot" orgasm in conjunction with a clitoral orgasm can send me off the edge for a good 15 minutes. I love it.

In laymans terms: For me, the innies are shorter and more frequent...and encourage the intensity of the outies. When the happen at the same time, my orgasm can last 15 minutes!

Practice makes you happy.

Ophelia

PS. I like innies the best when my girlfriend is using a strap on from behind. But she can palm a basketball...so her fingers have no trouble locating the spot!