In 2268 she was chosen to be the "drill thall" for Ensign Chekov when he, Kirk and Uhura were transported to Triskelion from the USS Enterprise by the Providers. As Chekov's drill thrall, she was responsible for his training, and providing him with nourishment.
During their first encounter, she commented on his name, which she first interpreted as "Chee-koo" and later "Chee-koof," describing it a "a very nice name." Surprised by her deep voice, the nervous Chekov, who was unsure if she was even female, remained polite towards her advances on him. She proceeded to grab his arms near the shoulders and gave him a squeeze, telling him that he was "a fine specimen" and that she liked him "better than the others."
Tamoon had plans of instructing Chekov well, so that her Provider would take him, and if the Provider is pleased with the result, he may "select" Chekov and Tamoon for each other.