i am having the same issue! I am very much looking forward to everyones replies:>every time max does something naughty/dangerous we tell him no, he starts laughing and does it even more. we were told to ignore it but obviouly not possible when he is doing something dangerous! we have no started to do the time out thing. but it's not working yet and to be honest i think he is a bit too young to understand but time will tell, am giving it a go anyway! max is 13months