Slimegirls secrete small amounts of liquid all over their body all the time. This does render them incapable of doing many jobs, including those involving machinery and paper, but their secretions are valuable material for magical and some technical purposes.

The scent and volume of these liquids changes with arousal. During sex, it feels like you're drowning in buckets of a pussy juice + sweat combo. The smell is pleasant and intoxicating. Not to mention the softness of her body and the possibility of penetration into any place you'd like...