lebornaciar:

no, anon, my feeling is that you’re right in not having been able to find an equivalent figure. the celtic cultures grew up in a different way than the greek and roman cultures did, with different conceptions of wildness and sexuality. for one thing, you’re much less likely to find references to wine at all (especially as you go further north), and much more likely to see connections to ale, and ale is likely more associated with kingship than with revelry. for another–though this is by no means universal–the figures most strongly connected with sexuality in the celtic traditions are often female, the sovereignty goddesses. you’re not likely to find a masculine fertility figure leading a bacchanal in the celtic wilderness.

there are some deities who have liminal field-and-forest association, and who may also have connections to sexuality, though in my experience many of the devotees of these deities feel that the popular hyperfocus on their sexuality aspects is somewhat overblown. the ones who come to mind are flidais, in the irish tradition, and cernunnos, in the gaulish. however, they are absolutely not equivalent figures to the greco-roman deities you asked about; they merely share some associations. they’re both more associated with liminality than anything else, and while flidais in particular does have some sexual associations, cernunnous has more to do with the fertility of the land than human (or divine) sexual fertility.

so, you may perhaps want to look into flidais or cernunnos, or other gods connected to them–but if you’re really bent on someone like pan, faunus, or dionysus, your best bet is to turn to them.