не дърпай дявола за опашката!
(do not pull the devil by the tail) •
It is used in a situation where someone is saying something dark and the rest tell him to don't push his luck and call for the bad things to happen
"Сигурно ще ни изпитват днес по химия" - "Тихо, не дърпай дявола за опашката!"
"They will most probably examine us in chemistry today" - "Keep quiet, don't pull the devil by the tail"