More devil's advocate:
Let's say that you want to create a religion in your campaign specifically intended to cause "squick", because it is a central pillar in your conflict structure that your protagonists are involved in. Your protagonists do not need to engage in, believe in, worship, or in any other way partake in the religious devotionals of this deity.
However, this deity is a neutrally aligned (Neither wholly good, nor wholly evil) goddess with spheres of influence governing motherhood, female sexuality, female powers of seduction (including how they can be used for intrigue and gaining hidden secrets through pillow talk, as well as a tool for political assassination), and a number of other things. This goddess really gets off on sex. REALLY. So much so, that her altars are stylized depictions of vagayjay, and part of the rituals of supplication involve pouring oils on the "clitoris" part of the altar, and giving it a good rubbing. Such a religion is not outside the realm of plausibility, especially if the goddess really does give good boons to her worshipers, and grants some serious buffs for stealth type female characters.
They are involved in the plot structure as part of a religious angst by your more stereotypical puritan 'Good' religions, who consider this goddesses devotional rituals to be simply lewd displays of sickening filth, and other epithets-- and you may even throw in some defilers, who simply oogle and fondle all the statuary, which angers the goddess. (She wants to be WORSHIPED, not GROPED.)
Even if such a religion is not really central to the campaign itself, its presence in the setting can add some interesting colour to the setting, if used appropriately.