How does one say "sixth sense" or "feminine sense" in Latin?
Sensus sextus, sive sensus muliebris.
Sensus is a perfectly fine word to use, and in fact sensus sextus is in use in nineteenth century Latin (at least, probably earlier if you look), which a quick Google search confirms. I don't believe a Classical citation for it exists, but they were familiar with the quinque sensus.
Either femininus or muliebris would have worked, but I chose the latter to avoid the grammatical associations with femininus. I don't believe either are attested with sensus in antiquity, but once again Neo-Latin gives an attestation, as I've found sensus muliebris in a sixteenth century text of Philo Judaeus, though the index points to a page in Greek, not Latin.
Sive is common in titles of works, and functions similarly to vel.