This has always been my favorite part of an exam. And my favorite doctor, a tall, attractive brunette, had a special way of doing abdominal exams. She would ask me to lie back on the table and to open my pants. Then, once my briefs were exposed, she'd reach in and use her fingertips to pull them down until the bunched waistband and fabric were just barely covering my penis, with plenty of pubic hair showing. She would always take her time and palpate deeply and carefully, including in the soft tissue just above my pubis, deep in the hair.
Once in a while, as my cock stiffened, her fingers would brush it through the fabric, by accident. I loved those moments more than actual bare-genital moments like testicular exams.
I loved everything about being examined this way... the crinkle of the paper, my fumbling with my belt, my pants coming open, feeling her stripping down my underwear and the cool air on my exposed belly and pubes, her careful pressing in that normally private and very vulnerable area... and fantasizing about her offering to masturbate me (which never happened.)
In contrast, my current doctor, a young man, never performs abdominal exams at all...at least, not as part of a routine physical.