Red rod

From A Wheel of Time Wiki

It is described as:

A rod, as thick as her wrist, bright red and smooth and rounded, firm rather than hard for all that it seemed to be stone; it did not warm slightly in her hand, it almost felt hot! Not real heat…^[1]

It makes Elayne think of Fire and when she channels Fire into it, she passes out and wakes up the next morning in her shift.

What happened?" Elayne demanded, and Nynaeve shook her head grimly.
"You don't want to know." Her lips twitched. Aviendha's face gave away nothing. Birgitte's mouth might have been a little tight, but the strongest emotion Elayne felt from her was a combination of relief and hilarity! The woman was doing her utmost not to roll on the floor laughing!
The worst of it was, no one would tell what had happened. What she had said, or done; she was sure it was that, by the quickly hidden grins she saw, from Kinswomen and Windfinders as well as sisters. But no one would tell her! After that, she decided to leave studying the ter'angreal to somewhere more comfortable than a inn. Somewhere definitely more private!

All evidence, including the shape and flexibility of the rod, seems to indicate that this ter'angreal is some sort of sexual aid.

[edit] Notes