“You know there’s grass, and then it got mowed, a landing strip,” one boy deadpanned, instigating a round of laughter. “If there’s grass on the field, play ball, right, right,” Vernacchio agreed, “which is interesting in this rather hair-phobic society where a lot of people are shaving their pubic hair - ” “Some people say it’s an orgy, some people say grand slam is a one-night stand. “Now, ‘grand slam’ has a bunch of different meanings,” replied Vernacchio, who has a master’s degree in human sexuality. talked about that made me feel really good was that penis size doesn’t matter”). “Grand slam,” called out a boy (who’d later tell me with disarming matter-of-factness that “the one thing Mr. Arrayed before Vernacchio was a circle of small desks occupied by 22 teenagers, six male and the rest female - a blur of sweatshirts and Ugg boots and form-fitting leggings. “Give me some more,” urged the fast-talking 47-year-old, who teaches 9th- and 12th-grade English as well as human sexuality. His goal was to prompt the students in Sexuality and Society - an elective for seniors at the private Friends’ Central School on Philadelphia’s affluent Main Line - to examine the assumptions buried in the venerable metaphor. “First base, second base, third base, home run,” Al Vernacchio ticked off the classic baseball terms for sex acts.