Another idea

"Or what?" Sarah answered in a curious tone.

"Or we could keep playing, I have an idea to make everything spicier," Katie continued.

"This is not a good sign but go on" said Sarah.

"What do you say to gasoline... like that?" In underwear? After all, we do not have to stop playing, it will make the journey even more fun" Katie said in a provocative voice.

"I hope you're joking, you would not do it either" Sarah answered, a little nervous.

Katie thinks for a moment and said: "Let's do it like this: if you do, you can continue to challenge me and it's up to you"

Sarah continued to be excited about the challenges so she did not back down and accepted Katie's proposal. It was enough just to make gas in underwear, which will never be.