I can't help but sense a bit of frustration here on the part of some.

As time and boredom strike me I hope to add more.

1. Joint cracking has some negative social implications that seems to have really messed with some people's heads.

2. Joint cracking has not been significant enough of a health problem to interest the medical community.

3. Joint cracking is ubiquitous throughout the population.

As a result of the above, since joint cracking is found equally in all types of people: some people who crack their knuckles have arthritis and some people do not, some have Obsessive Compulsive Disorder and some do not, some have vertigo and some do not. . .

Some of the people who have arthritis and crack their knuckles blame their arthritis on knuckle cracking.

Some of the people who have OCD and crack their knuckles obsess about knuckle cracking.

Some of the people who have vertigo and crack their knuckles blame their vertigo on knuckle cracking.

I have a pen that is larger than average and when I grip it just right it will crack the base of my thumb. It's funny because it only happens with that one particular pen and no others.

The main problem with answering this question is that the info. is a bit too vague. I too occasionally feel the sensation of "cracking a knuckle" at the base of my p***s during s*x. For me it involves the joint formed by the pubic symphysis where the suspensory ligament of the p***s attaches. This MAY be what you are feeling too.

For me there are two main joints that I crack involving my sternum. The one that feels the best is the Sterno-manubrial joint at the "angle of Louis". The second is the sterno-clavicular joint (on either side).

The sterno-manubrial joint feels better than any other in my body but is the most difficult and rare to make work.