up to (one's) (old) tricks
Doing things that one was known for doing in the past, especially deceitful or mischievous behavior. Food went missing from the school cafeteria? It sounds like Billy is up to his tricks again. I reunited with my two best friends after nearly five years apart, and we were up to our old tricks again in no time.
up to your tricks
or up to your old tricks
COMMON If someone is up to their tricks or up to their old tricks, they are behaving in the same dishonest or foolish way that they have done in the past. Homeowners wondering if estate agents are no longer up to their tricks should think again. They seemed to be up to their old tricks of promising one thing and doing the opposite.
up to your (old) tricks
misbehaving in a characteristic way. informal