Building to get to the O

Yup. It's called muscle tone!

What do you mean muscle tone? Explain.

By "muscle tone" I understand it as awareness of the muscles at the base of your penis and in particular, those the control your pee flow. There are a number of ways you can sense this. By clenching your anus tightly or lightly and developing a sense of tweaking gently and becoming aware of the variety of tweets from the most minimal to the strongest. When the Aneros is in, you can try this out. Give a hard squeeze and hold. Then relax and try a little hint of contraction. All this will increase your awareness of your muscle structures underneath. I know I've written it so clumsy but I hope it helps!