What does Bethany try next?

Mechanical intervention

The sensual brunette knows when she's beaten and wastes no more time upon an obviously unsuccessful strategy. With a sigh, she takes her victim's toes out of her mouth, stands up and prances over to your boxes, instantly laying her hands on what she seeks: a bulbous pink vibrating wand with removable head. She plugs the device into a wall socket and hurries back, switching the smooth head for one sporting a hedgehog-like mass of soft rubber spikes. You're about ready to call a halt and have Skylark pleasure you, but curiosity makes you hesitate and moments later, you're very glad you did.

Bethany strokes the spines lightly down your guest's arch and she screams into the cleft between your cheeks as a jolt runs through her whole body. The effect is like the vibrator had given the young blonde an electric shock and you can feel her simultaneously sobbing and laughing even while she redoubles her efforts to **** her tongue fully into your crinkled arsehole. Amazingly, she still manages to keep her feet in place, but you doubt she'll manage for much longer now that your grad student has her measure.

The spiky crown teases its way around foot and toe, whilst Bethany adds her fingernails to the maddening sensations and the tremors in the younger girl's limbs become more pronounced. The only question is whether her fortitude will outlast your ability to resist sating your carnal lusts.