None of the characters behaved in a promiscuous fashion at any point in the game. There are things which may hint at it - for instance, Tifa's costume and job, Yuffie's enthusiasm to chat with the Seaplane Guy after disembarking at Costa del Sol. However, they all showed that they have standards too. Aeris never layed a finger on Cloud, and Tifa was very annoyed at the prospect of the boys looking at her while they were climbing the stairs in the Shinra complex.

None of the characters actually behaved in an openly dodgy manner, though.