Lekku

"A Twi'lek should know how to handle her lekku. They're our most erogenous organ."

- Hera Syndulla

Lekku, also referred to as head-tails, were prehensile, erogenous organs of the Twi'lek species, who referred to the left lekku as tchun and the right as tchin.

Biology
"I don't think the Emperor was exactly thinking about what we've just done when he was handing out his reformation acts." "The shriveled old man wouldn't even know that lekku can be used that way. I was surprised, myself."

- Hera Syndulla and Kanan Jarrus, on Sheev Palpatine

Lekku were thick, fleshy tendrils with pointed tips. Some lekku were mottled. Twi'lek lekku were prehensile, capable of twitching, wriggling, swaying sensually, or curling, and could be used to touch or stroke as one of the body's erogenous zones. Some claimed that they were the most erogenous organ, and even contained certain memories&mdash;to the point that damaging one was tantamount to damaging the brain. Hera Syndulla once jokingly referred to them as her brain.

Culture
"That feels great, Hera," he said. "Guess those things aren't just for show."

- Kanan Jarrus, to Hera Syndulla

Twi'leks referred to their left lekku as tchun and the right as tchin.

Twi'leks were highly protective of their lekku, and believed one should know how to handle them properly. Some wore headdresses around them. As erogenous zones, they could be incorporated into sex and foreplay, being stroked, kissed, or licked. They were capable of stroking the male member in a similar manner to a handjob, either gliding along either side or wrapping around the shaft to stroke or squeeze more fully. The act of stroking the penis with both head-tails was known as lekking.