He’s hired a small boat to take you rowing on a remote lake….
Sitting on the seat opposite him, stretch out your bare toes and massage his groin. When he can’t take the pleasure any more, sit on his lap and tell him to ‘keep rowing, boy’, while you take advantage of his forward-thrusting pelvic motion. Grind down on him, achieving extra thrust by planting your feet on the seat opposite. (If your legs don’t reach it, sit astride him.) Synchronise your rhythm with his rowing motion and use your vaginal muscles to caress his shaft.
Splinter alert: he’s advised to sit on a shirt – and you should avoid rubbing your thighs against the seat!