NSFW What causes this amazing texture and how long does it last?

Welcome to hump day! Another frivolous titillating question from inquiring minds.

After coitus and sometimes before I notice that the penis is velvety soft. A velvet so fine that human hands can’t fully discern the texture. I briefly tried googling this and found all manner of interesting and unrelated garbage. Is there a scientific reason behind this?

I don’t believe it alone could caused by friction as alternative methods of play don’t seem to yield the same results. Or not so I have noticed.

So that leaves either a compound in nature’s lube or a combined effect of the two. Has there been any studies done in relation to this?

How long would this effect last? If the silkiness was caused by a chemical compound have dermatologists or pharmaceutical companies tried to replicate it? If they haven’t already, do you think that they would benefit by marketing it as a chemical replication of a bodily secretion?