No current EA/Maxis official mod exists. You need a third-party mod. The most reliable free version is often part of broader "sugar life" or "ho it up" style mods, or a standalone interaction mod.
This is the most direct standalone mod matching your query. After your Sim completes a WooHoo and enters a "Flirty" mood, it adds specific friendly social interactions to ask for §1,000 or §3,000. You can find this on the One89 creations thread on Sims 4 Studio . sims 4 ask for money after woohoo mod download free
Happy Simming, and remember: Cash is King! No current EA/Maxis official mod exists