thinking too much certainly does not help with sex
My arsenal for this includes: Beer, wine, wine coolers, hard cider, stoli vodka, malibu, rum, champagne, cbd isolate sublingual tincture, music, Hue mood lighting, candle-like scents, soft sheets, massage, MIV, cell phones in the microwave (faraday cage), and not talking about anything current.
If involved parties aren't relaxed, it's unlikely to be that good.
But it isn't the always greatest thing for the actual sex.
"Just be yourself" essentially means "Stop thinking... about how to look confident, how to impress her, etc." Such thinking usually yields the exact opposite effect.