How do I know if my burm is ovulating?

[GyGbeetle]

All but 1 of my snakes were purchased as babies or almost yearlings, including my burm, so I have limited experience with adult/mature snakes. She's grown a lot since her gotcha day in October 2016, and I'm wondering if she's starting to ovulate. Without an ultrasound machine, I'd like to know if there are any tell-tale signs of this. She looks swollen, has been a little "hissy" off and on lately, but otherwise, she seems her normal self. And I'm not finding a lot of success Googling this question; most of the answers pertain to gravidity and not ovulation.