To fawn over is to flatter somebody shamelessly to win their favour. Fawn over a guest.
The image is a dog rather than a young deer, from an old verb meaning to be glad. To fawn over somebody is embarrassing to watch and effective more often than it should be.
1phrasefawn overTo flatter somebody shamelessly to win their favour.
“The whole table began to fawn over him the moment he arrived.”
fawn over is an action.