What is the meaning of "stay regular’ please
A little more of the text from which this has been transferred would be helpful.
I stay regular with the help of eating fruits daily
go to the toilet regularly, avoid constipation 
Ganesh, that WAS my first thought, but I thought perhaps it was a too ungentlemanly answer. Never mind, you’ve done the job for me. Thanks. LOL.
Could also have meant, " Please stay in regular contact "