Give someone butterflies

To have overwhelming excitement when you see someone you have feelings for;

or a feeling you get when someone you love kisses or touches you.

 

Examples)

Every time Cynthia kisses me I get butterflies; saying "she gives me butterflies".

It's a good thing to give someone butterflies

Falling in love gives you butterflies.

 

https://www.urbandictionary.com/define.php?term=give%20someone%20butterflies 

Urban Dictionary: give someone butterflies