If you're not overly strict, and you show tolerance and mercy when someone does something wrong, you're being lenient.
Lenient means tolerant or relaxed, and is usually used when we’re talking about someone’s attitude toward discipline. In 19th-century child-rearing books, we often read about strict teachers who punish children just for squirming in their seats. These days teachers are more likely to be lenient, more understanding. If you're a big fan of discipline and punishment, however, lenient might mean "soft" or "indulgent."
adj tolerant or lenient
adj characterized by tolerance and mercy
(used of persons or behavior) inclined to show mercy