A demisexual needs to have an emotional connection with someone before any sexual feelings can appear.
One-night stands have zero appeal for me, even when I’m gagging for it.
You are far more likely to make an emotional connection by having a good conversation at a dinner party, or hanging out with friends of friends in places where you can actually hear each other speak.
If having sex with someone you don’t fancy isn’t fun and doesn’t give you pleasure, why do it? Save yourself the spine shudders of thinking back on sex with people that give you 'the ick'.