Rest
You keep your tongue to your self to give your heart a rest. You’ve been talking and moving your tongue around all day expressing your feelings. This has tired both your tongue and your heart out, so you stop your tongue moving and decide that you need some self rest time.
It's important to let yourself rest every now and then, you know.
けい
いこ
None
What better way to rest than to eat some cake (けい)! No talking necessary. Just enjoy the delicious taste of cake on your tongue and feel your heart let out a sigh of relief.
You should rest right now. Take a break from Japanese and go eat some cake. (Just remember to come back when your tongue and heart are sufficiently rested!)