at home
if you feel at home in a particular situation, you feel relaxed, comfortable, and happy
Melanie is equally at home singing oratorio, spirituals, jazz or performing in musical theatre.
if someone or something looks at home somewhere, they look as if it is normal, natural, or appropriate for them to be there
The 16-year-old's huge shoulder and arm muscles would look more at home on a male hammer thrower.
Easy Learning Idioms Dictionary. Copyright © HarperCollins Publishers