As a disclaimer - this is not something I've tried. This was the approach taken by the father of one of my college roommates, so any testing of the theory is a good 30 years old. That said, I think it's genius.
Put a tent in the middle of your room. Girls walk in, say "oh wow, a tent!" climb into it and lie down.
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Or, if that doesn't sound like a good idea,
these chairs are awesome.