godan verb (-ru), intransitive verb
eat at Denny's
Dated slang from the late 20th century, used among young people to mean going to or eating at the Denny's family restaurant chain. Now mostly a nostalgic or retro expression.
放課後、みんなでデニろうぜ。
After school, let's go eat at Denny's.
あの頃
Back then, we used to eat at Denny's a lot.