"This is so weird but ... Oh Gawd!" Alan thought as Susan's fingers reached the top of his inner thigh and lightly brushed his vulva. It was was maddening and enticing and confusing and delicious all at once. As Susan's fingers neared the apex of his thighs, Alan anticipated the thrill and delight of her fingers moving to his testicles. Instead what he received was a moment of confused frustrated undefined need as Susan's fingers drifted even higher than should have been possible. This momentarily confused kinesthesis was instantly overwhelmed by the delightful shock of pleasure that pulsed through Alan's body when Susan's fingers incongruously penetrated his crotch and sent mini explosions coursing through his body that were vaguely like the feeling of approaching orgasm but at the same time, weirdly inverted. Instead of a well defined focused goal of release, it was a strange undefinable need.
Alan could hear feminine gasps and squeals. A small part of his mind recognized that the woman making those noises was himself, but Alan was focused on Susan's hand's. Susan was no longer caressing his thighs, but instead was rubbing and penetrating deeper and deeper. This scared Alan at first. Susan's finger felt huge at it entered places Alan was not supposed to have places to enter. Accompanying the fear was an electric delight followed by that weird inverted desire for yet more.
Vaguely aware of the increasing screams and moans of that woman that accompanied his own delights, Alan responded as Susan practically lifted him one handed to a kneeling position that matched his own unfocused desire for more.