Going on holiday with your friends under the pretense that you'll be playing rugby. Possibly with the addition of something charitable to make it easier to sell to your significant other.
Specific requirements for tour: At least two nights away, playing at least one game in another country, with three consecutive drinking sessions. It still counts if you don't drink, but a session had to be happening.
If you don't play, it's not touring - you're merely an independent observer, a bit like the UN.
Everything else isn't touring - one night away, watching instead of playing, etc.
See also Domestic Touring
"Now we're touring"
"I love tour"
"Never trust a fart on day 3 of tour"