Maschalagnia
Maschalagnia is an armpit fetish — sexual arousal from armpits, whether their look, feel, scent, or the act of playing with them. It's especially associated with a love of hairy, naturally-scented underarms, where for many enthusiasts the stronger the natural smell, the better. Play can combine sniffing, licking, kissing, and touching the armpit, and some enjoy 'pit jobs' (using the armpit for stimulation). It overlaps closely with scent fetishes (olfactophilia) and body-hair attraction. The mix of intimacy, scent, and a rarely-eroticized spot is central.
The armpit is intimate, private, and scent-rich — eroticizing it taps the primal pull of natural body odor (a big draw for many) plus the taboo of desiring a 'non-sexual' spot. For hairy-pit fans, the fur and funk together are the appeal.
It might mean sniffing, licking, kissing, or nuzzling a partner's armpit, enjoying it hairy and unwashed, or using it for stimulation ('pit jobs'). It often pairs with going natural — skipping deodorant to let the scent come through.
Low-risk. Basic hygiene applies (or is deliberately skipped for scent play), and if licking, mind any deodorant residue or irritation. Otherwise harmless.