Smallest for me was a friend who was 2.5-3inches raging hard. Hardly much frenulum or any ridges to it. Very smooth-skinned cock. No visible veins, usually pale and flaccid in his wispy blond pubic hair. Reminded me a lot of a white marble chess piece when erect.
We first met at a gaming convention where he followed me around like a slave trying to get a shot at me. We shared a hotel room and he spent most of the night licking my thigh-high leather boots. (I was LARPing as a Giovanni vampire inquisitor.) I was fascinated someone shared my boot fetish. We never touched each other's genitals, but both of us were so aroused from the sensation of my boots and the mutual reaction. He came in his pants and I was tired enough to pass out with him.
Fast forward to several years later when I'm single again and I return to him, demanding we be lovers now that we were free. (He just suffered a brutal breakup and gladly accepted.) He ate me out ass and pussy for two weeks solid before I ever saw his penis. He worshipped my pussy. Best head--or at least the top 3 of my life. One day, I couldn't take it anymore not reciprocating (he cited health reasons) and yanked his pants down. He stopped breathing.
And then I realized I CAN DEEP THROAT THAT! I was swallowing the tip of his head down my throat and sucking so hard. He came in minutes and gasped he hadn't been able to come from head before. I was like a cheshire cat. Loved his small cock. Anal was always smooth and easy.