Girlishly

Tom giggled girlishly.

He had dropped behind Du Barry for a moment to tie up his bootlace, and Julie, running girlishly along the moonlit path, bumped violently into his arched back.

Ganymede was once a girlishly handsome precocious youth. That one cannot for any considerable number of years go on being youthful, girlishly handsome, and precocious, seems on consideration to be a statement as worthy of credit as the famous syllogistic conclusion, "Socrates was mortal."

"What's worse, I suppose I girlishly trilled all this to him, and too often. […]"