Given how muscular a lamia's tail is. I wonder if a lamia overstuffing herself, and clenching her tail up near where it connects to her upper half would put a lot of pressure on her vagina?
Now that I think about it, putting her in a corset, and tightly binding her tale could be fun.
It would have a similar effect, but unlike stuffing where blood is being diverted to her digestive tract, her body would be looking for places to take more blood as she is compressed, and one place that could take more would be her genitals, since for men and women, more blood going to and filling parts of the genitals is part of arousal.
Plus I imagine having her tail gradually cinched would be very stimulating for her.