Seems like if she’s interested, she might invite you in for a drink or coffee next time you drop your kid at their house. If she’s too shy, maybe you offer next time she drops her kid at your house. If she stays in her car as little Billy runs up, that’s a sign she’s not interested (or just busy at that moment).
I also like the idea of offering to take the boys to a movie or something and inviting her. But she may just want to see a movie, so that’s not a total green light. If she grabs your dick during the movie though, that’s a pretty good sign.
“On one side, a delicious coconut cream cake. On the other, a steaming pile of dog shit with orange icing and bits of hair combed over it.”