Hello Friends,
The ancient KamaSutra categorizeses three male and three female size categories. It generalizes pairing with each size group, resulting in nine variations. Thanks to the BDSM Kink folks who are willing to provide photos of pussies and cocks and commentary about preferences, I see the situation is more complex.
The appearance of individual sex organs has many more variables. Beyond function, it then becomes a matter of preferential erotic stimulation based on sight and also preferences in touch/feel, especially in oral sex.
How your partner responds will encourage the development of a relationship once the preliminary preferences bring you together.
Before this openness, people could only play sex roulette and hope their partner, and they were a match and compatible sexually.
Long-term relationships would be more successful if people could understand their preferences, find ways to find each other and have a test relationship before committing. Hopefully, all other relationship factors can be satisfied as well, I.E., personalities.
That is, if the partners want a long-term relationship.