warm the cockles of someone's heart
warm the cockles of (one's) heart
To cause one to feel happy. The "cockles of one's heart" are the deepest part of oneself. Thank you so much—your kind words really warmed the cockles of my heart.
warm the cockles of someone's heartgive someone a comforting feeling of pleasure or contentment.
This phrase perhaps arose as a result of the resemblance in shape between a heart and a cockleshell.