Teresa and Joe Giudice -- I Got Some Prison Advice For You ... Says 'Freeway' Rick Ross

"Real Housewives of New Jersey" stars Teresa and Joe Giudice could get their heads cracked open in prison if they don't follow one simple rule ... so says convicted drug trafficker 'Freeway' Rick Ross.

Rick spent 13 years in the pokey after his L.A. drug empire collapsed in the '90s ... so he knows a thing or two about life behind bars -- and he's got one important piece of advice to maintain the peace.

Here's a hint ... less Real Housewives ... more Jerry Springer.

Just watch. Especially if your last name is Giudice.