So Kinzie Kensington mentions in the introduction dialogue for the mission in which you free Zimos that her safe word is "Teacup". I checked the wiki, and the only mention is in her banter with Tanya between missions, after the latter told her she would be a major draw at a brothel.
Is this the only time she uses her safe word, or does she use it at other times as well? I sort-of remember her using it in my playthroughs, and I didn't really bother with homies.