like a dog with two tails
US /laɪk ə dɔɡ wɪθ tuː teɪlz/
UK /laɪk ə dɔɡ wɪθ tuː teɪlz/

1.
extremely happy and excited
:
•
When he heard the good news, he was like a dog with two tails.
•
She'll be like a dog with two tails if she gets that promotion.