If someone does something staidly, they do it in a serious, calm, and proper way, without being silly or loud.
Staidly is a good way to act in some situations, but it can also make people think of being boring or old-fashioned.
Examples:
She walked staidly into the room.
He staidly sipped his tea.
The man spoke staidly to the children.
The cat staidly watched the mouse.
The queen staidly waved to the people.
The dog staidly sat on the chair.