They said hermaphrodite

“Yes, they are, at least with many species. Do you see the very small opening about four inches lower, almost behind me? That is another cavity used in sex called the Leska'olo, or 'Lower Opening'. Some species need a more rear-facing entrance for sex. It also allows us to copulate with each other. If we only had one opening, two of my race could not be inside each other at the same time. The geometry would be all wrong. So, one partner inserts into the upper opening, and the other inserts into the first person's lower hole."

"We have a similar opening, but it is mostly used for waste elimination. Some enjoy having sex there."

"I understand. Some of my species are Sarska-olokrum, or those who prefer to be penetrated in the upper hole. Others are Leska-olokrum and prefer the lower hole. A small percentage have no preference and are called Udro'krum or 'confused'. Now would you like to see my male sex organ?”

“Yes, but where is it?” he said looking all over the area.

“Here,” said the alien. As he watched, a tiny slit about halfway between the two holes opened and out pushed a greenish, fleshy rod that was remarkably penis-like, except it had no cap and was smooth. It was about an inch across and just kept coming out; when it stopped, it must have been at least fifteen inches long.

“Wow! You’ll be popular with the ladies!” Aaron exclaimed with a laugh.

“What do you mean?”

“Well, the average human penis – that’s the male sex organ – is about six inches. Some rare individuals get up to twelve inches long and three inches thick. That looks to be fifteen. Some women prefer large penises, like nine or ten inches.”

“Well, I can also change the width of it too. From between half to five times this width. We call it a 'wiki'a'.”

Aaron was impressed and a bit jealous. “That’s special.”

“Well, some species require the large penis to achieve proper pleasure. The Woowoogans need the full length and girth to stimulate their pleasure spot in the back of the female’s vagina.”

Aaron was intrigued by the alien’s sexual equipment. “May I touch you?” he asked a little cautiously.

“Please. Your fondling and curiosity have me rather horny right now. Touch me anywhere you like."