How to make a kid aware of lack of swallowing/managing secretions?

Hi guys! I’m a school based SLP and I have a kiddo in life skills who is non speaking (he just came to us and I’m working on getting him a device). He is stationary (in a stroller). His teacher reported that he doesn’t swallow so he builds up a lot of secretions in his mouth. I am not as familiar with the swallowing side of speech and am looking for any suggestions on how to make him more aware of the fact that he isn’t swallowing. If you guys have any suggestions at all, I would greatly appreciate it. I was thinking something along the lines of a visual to remind him to swallow, but I’m not sure if there are better suggestions out there. Thanks in advance!