Physiologically, there are certainly differences in design and function, but for practical purposes, it's more similar than different. A fairly specialized organ longer than it is wide for depositing genetic material and experiencing nerve stimulation that aid in boosting serotonin levels and easing social bonding is a pretty common approach by evolution. Nadayki certainly enjoys the attention, sighing throatily at the touch, wrapping his fingers in Mort's hair again. With the other hand he reaches back to deal with the rest of the jumpsuit.