How do I get my girl to flirt?

So I sent my girl of 5+ years a sexy meme that had an inappropriate but sexy af pic that said “out of all my toys… you’re my favorite” 😏

She responded with “that’s interesting lol” 🙄

I said “interesting?”

She said “I mean, I dunno?”

Seriously… wtf? How do I let her know that the way she responds isn’t sexy or flirty and when I’m obviously trying to be hella playful via text that she should maybe try to be fun, sexy, flirty, and playful back?