questions on contractions

It is, indeed, your anal sphincter, ie, your arsehole.

To get the involuntary contractions going, just contract it the slightest amount, like barely holding in gas.

It is definitely a case of less is more. Then, as described by B Mayfield, do relaxed deep breathing into your lower abdomain.

you are looking for even the slightest feeling of pleasure at first.

as B Mayfield advises, just keep that slight contraction and do the breathing and let yourself feel the slight pleasure. It takes a while, but after you recognize that, you will start to find more pleasure.

Once you do, as part of that pleasure, your sphincter will start to quiver in sexual excitement, which amplifies the pleasure.

Don't concentrate on making the involuntaries happen. Instead concentrate on enjoying the small pleasure and letting it grow.

Plus: lots of internal lube, and make sure the abutment is in the right spot.

Darwin