In my 20s, I took a girl back to her apartment after our second date. (On the first date, she had taken her top off and let me suckle her breasts before losing her nerve and backing down.)
She took the initiative, unfastening my pants and taking my erection into her mouth. I had a short foreskin which rolled back anytime my penis stiffened, so it wouldn’t have been visible. And it was dark in the room.
After a minute or so of sucking my penis, she leaned back and said, “I can’t continue with this.” Unwilling to push against a “no,” I nodded, zipped up, and left. That was our last date.
Several possibilities: She was coming off an abusive relationship and acting erratically; she’d had too much to drink and either felt nauseous or didn’t trust her decisionmaking; or, she detected my foreskin and wanted none of it, but wouldn’t say so.
I’m leaning toward the third because, in those days, I was fastidious with hygiene but probably erred in that, scrubbing my glans with soap-and-water, then drying it. I have noticed that treatment brings on the sell-by date much sooner than just rinsing with water and leaving the surfaces wet.