"Nice stretch, good response," she mutters as her arms plunges far into your bowels. You can feel her squirming around in there. Then you gasp as you realize that's her shoulder against your buttocks! "Yes, definitely good depth." she responds before suddenly pulling her arm free.
"My god! Are you... gasp... saying some of the lessons need people to... go up there?"
"Yes," she says as she washes her arms, "though those tend to be advanced courses." She comes back to you, still at the bottom end of the bed. "There are also classes on this too."
"EEEEEP!" you manage as she thrusts a hand into your sex.