bill and coo
US /bɪl ənd kuː/
UK /bɪl ənd kuː/

1.
卿卿我我, 亲热
to show affection by kissing and caressing, often in a public or overly sentimental way
:
•
The young couple was billing and cooing in the park.
那对年轻夫妇在公园里卿卿我我。
•
I can't stand to watch them bill and coo all the time.
我受不了他们总是卿卿我我。