In another strip, Florence thinks she's startled Sam, but he explains: "No, you did not surprise me. My plans to scream like a little girl when I reached the kitchen were made hours ago. It's pure coincidence you happened to be here at the time."
Nodded to in Something*Positive where Aubrey tactlessly reminds Davan of the time when he was a kid, was attacked by a dog, and wet himself in public, then she reassures him that his screams didn't sound girly. "A little like a boiling lobster, but not girlish at all."
DuPree: Oh my Gosh! I'd know that girlish scream anywhere!
Referenced in Ozy and Millie. Millie finds herself holding something she'd rather not. She asks Ozy how she can let go without screaming like a little girl. Ozy's answer? "You ARE a little girl." Millie takes the hint.
In Tales of the Questor, when Quentyn prepares to wash Sam's clothes and finds them full of fleas, the Unsound Effect is "GIRLY SCREAM."
Referenced in DM of the Rings during the Helms Deep fight, when Legolas insists on counting kills.
Gimli: Okay, let me tell you how this will work. You and I kill an orc an average of once a round. You are ten kills ahead because you've got a bow, whereas I had to wait for them to scale the walls before I could start killing.
Legolas: Woo-hoo! Who's the elf?
Gimli: Therefore, you will REMAIN ten kills ahead of me...
Legolas: SAY IT! SAY I'M THE ELF!
Gimli: ...until you run out of arrows and you have to use your little 1d4 dagger, at which point you will cease to make a meaningful contribution to this battle.
Legolas: Oh.
Gimli: And then you will begin screaming like a woman.