This is a regular verb. It follows the conjugation pattern of the verb hablar.
PresentPresente
Mi amigo coquetea con la camarera del café.
My friend flirts with the waitress at the café.
ImperfectPretérito imperfecto
De joven, coqueteaba con todo el mundo.
When he was young, he flirted with everyone.
PreteritePretérito indefinido
Tú coqueteaste con ella en la fiesta, ¿verdad?
You flirted with her at the party, right?