Tut-tut. All the above writeups are heavy (too heavy!) on the rules and consequences, but all too light on strategy, and on the
inhibition-stripping payoff of this game when played in a largish group of people (I would say six was about the minimum for a good game).
First of all, forget about sitting round a table; the more physically comfortable the participants are, the more candid and pissed they are likely to get. Also, let people drink as much or as little as they feel comfortable - the game can go on for hours when the going is good, and it's funnier if people are not throwing up in each others' laps. As for chairpeople monitoring whose turn it is, who cares? It's a drinking game, not The Weakest Link. And forget penalties! I would also hesitate to impose limits on the size of the group, as the best and funniest game of "I Never" that I've ever been involved in was played with a fluctuating group of coming and going participants who numbered about 30 at the peak of proceedings.
For the best results, it helps to have as mixed a group of people as possible; some who know each other intimately, some who are only just getting acquainted; some established couples and some people who may or may not fancy each other by the end of the night; and some ol' slappers mixed in with some nubile innocents.
And finally the strategy. At its ultimate use as a social lubricant, one plays in order to have a laugh at other people's discomfiture, and, in a sportsmanlike fashion, give them the occasional laugh at one's own expense. It's not about revealing shameful secrets and tarnishing anyone's name for ever, so I would encourage and indeed enjoin you to lie, lie, lie about anything that could cause you pain to have revealed. Just don't drink, how hard can it be? Oh, you're Irish? Oh well. Just brazen it out then.
You will find, as the game gets going, the drink gets taken and your turn comes around, that you will say "I Never..." followed by something outrageous that you definitely have done, and the challenge at this point is to remember the next morning who else sipped their pint. But for as long as you can remain relatively sober, the expert's strategy is to declaim something vaguely naughty or outright crazy that you know for a fact at least one of the people present has been involved in, and watch everyone else laugh or stare at them in amazement. So, for example, if I know that my happily married friend Mary had once come home from a party wearing someone else's underwear, I will say that and then glance at her smugly. Get it? It's a great way to let your friends' friends get to know them a bit better, and also - when played with finesse - to match-make by revealing choice facts about some people that you think other people will fancy.
Yes, scores will get settled, and one-upmanship will ensue, both in the "you are a bigger reprobate than me" and the "I'm a bigger reprobate than you" arenas. But, firstly, you can always avoid major damage to your reputation by, as previously mentioned, fibbing through your dentures, and secondly, if the people you're playing with are easily shocked then don't play with them in the first place. It is, apart from being a roaring laugh, a trust game; you don't judge people, and you trust them not to judge you in return. And hey, that's what a good night out with friends is all about, right?