I used to be quite nervous too jb - I think it's normal!! A "safe" bone would be one they can't swallow, so quite big. A chicken leg bone without the little bit that you can pull off or even a chop or cutlet bone should be ok. I introduced mince quite early and the boys were fine with that. Or you could scrape the meat with a knife into mashed potato or cereal or something like that. Letting them suck on a piece of beef is fine - if it's quite a big piece they can't swallow it, so maybe you would feel better with a bigger piece - if in doubt remember the film canister rule that's used for toys - if doesn't fit in a film cannister they can't swallow it LOL!