Five year old using words we don't want....what good parenting method am I missing to take care of this?

Our child is 5 years old and has gotten into using the word ';butt' frequently and also started doing raspberries (spitting with tongue out) all the time. The timing of both is to be rude, disruptive or attention getting. We tried to do the ';ignore'; method but his younger sister has taken up the act now. We have used time outs and pepper on the tongue threats. Not seeming to work. He is a very smart and sweet boy if we could get rid of this behavior. Has anyone else gone through this with their child and how did you handle it?Five year old using words we don't want....what good parenting method am I missing to take care of this?
What we did with our son was explain to him how it made him sound. We also told him that there were appropriate ways and times to use such words. And last, we always tell him that if he doesn't understand the meaning of a word he hears on the TV or else where he needs to ask the meaning before he uses it. This has cut down the embarrassing moments. He is not perfect but he is better.Five year old using words we don't want....what good parenting method am I missing to take care of this?
you cant change a boy from being a boy. and you cant change a little sister from following her brother, he is just being himself and he is picking up things from out side of your parenting. boys will be boys, but there is a limit and especially for his age.