Mismatches here disrupt the "tip-to-tip" alignment. Girth: Variations affect "shaft-to-shaft" techniques.
Efficiency is penalized by physical "mismatches" between individuals. The model identifies several critical variables:
Arranging individuals "tip-to-tip" to allow for a four-at-a-time stimulation rate per person (using both hands to bridge two pairs).
To eliminate geometry penalties, the audience must be sorted first by leg length , then by shaft length , and finally by girth .