be in (one's) element

To be doing something that one is very comfortable with or proficient in. My mother is in her element in the kitchen and can make just about any dish.

Common Names:

Name	Pronounced	Usage
Ganymedes	-	Greek Mythology
Gordana	GOR-dah-nah (Serbian, Croatian)	Serbian, Croatian, Macedonian
Lutgard	LOOT-gahrt	German (Archaic)
Vira	-	Ukrainian
Bahija	-	Arabic
Demetrius	[də'mi:triəs]