Let her have the first move

No way.... if you're cumming just from looking at her, then you definitely can't be going on the offensive right now.... you just need to bide your time, and wait until she lets you make her cum (or for an opportunity to take it from her!).

A happy smile takes to her face as she finishes her brief inspection, her eyes meeting yours. In a confident tone, flicking a backwards glance towards the still-closed door, Professor Phoebe places a hand on each of your shoulders and begins to slowly guide you down to your knees. Following along, the two of you end up kneeling just opposite one another, facing each other.

"Alright then." She says with a smirk. "Let's get to testing that endurance!"

In a sudden sweep of motion, Professor Phoebe begins grappling with you in almost the same instant as you're suddenly being pinned down on your back. Moving like an expert, she shimmies further down your body until her mouth is in line with your snatch, and then wraps an arm around each of your thighs as you lie on your back and she lies on her belly. Shifting into a kneeling position, she brings you up so that you're almost dangling from her grip even though your (surprised looking!) head and shoulders are still back on the mat.

In just a second or two, she's got you in this compromising spot, and she's just about to start going to work on you with her mouth!