In this initial investigation of interpersonal pleasuring, denned as the administration of positive physical stimulation to one human by another, 439 undergraduates used the Brock Pleasure Machine to give 30 intensity-graded waves of pleasure to a confederate recipient's buttocks. The findings of Experiment 1 were that pleasuring increased across trials and more pleasuring was given to an oppositethan to a same-sex partner. Experiment 2 replicated these results and revealed interactions involving sex combination and the manipulated attractiveness and responsiveness of the recipient. Responsive and attractive recipients elicited higher pleasuring in same-sex pairs. Responsiveness led to lower pleasuring in opposite-sex pairs, except for a male .pleasuring an unattractive female. Experiment 3 showed that anticipation of future interaction increased pleasuring. Experiment 4 showed that pleasuring was reduced following acquaintanceship with a dissimilar hostile recipient. Limits to a theory of interpersonal gratification were discussed.