The word or phrase to describe the action of pursing one’s lips in a tight rounded shape in a happy mood

As the title says, what is the word or phrase to describe the action of pursing one's lips in a tight rounded shape in a happy mood?

Merriam-Webster: purse(verb) defines it as (quoting from English Language Learners):

to form (your lips) into a tight circle or line

So "purse one's lips" can mean forming a line instead of a circle.

Cambridge Dictionary: purse(verb) defines it as follows:

to bring your lips tightly together so that they form a rounded shape, usually as an expression of disapproval

Example: "I don't approve of that kind of language," she said, pursing her lips.

So "purse one's lips" usually shows the feeling of disapproval (although I think it can also mean a happy mood).

But I'm trying to find a word or a phrase that specifically refers to "rounded shape" and "happy mood". For example, "So happy to see her boyfriend again, she ___ her lips to ask for a kiss from him." From our life experience we know that, in this example, when she "___" her lips, the lips don't form a line but a circle, and she must be in a happy mood.

I'm aware of this question What does the phrase "to purse your lips" mean？ [closed] but it doesn't answer my question.