Roleplaying games - be they on IRC or table-top - attract a wide range of age-groups. Anyone can join Wildcard, regardless of age. For that reason - as well as out of general respect - please mind what you roleplay in the main channel.
Nothing is prohibited in Wildcard. You can smut it up or describe the most violent acts your mind can cook up (pinkgothic does both frequently), but you should never subject the unwilling to such things.
That extends first and foremost to your roleplaying partner(s), where it goes without saying (they'll just stop RPing with you if you don't comply with that, after all)... but also to any people lurking in the IC channel(s). Make sure they know what they've gotten themselves into, or simply open a side channel.
As you play Wildcard, you'll get to know players to the point where asking them is no longer relevant - you're allowed to make educated guesses, but if you're found to avoid asking the lurkers or players on purpose, it's a one-way ticket out of the game for you.