Hey Johnny and welcome to Bluelight if you haven't already been welcomed. One of the first things you should do as a new member is to familiarize yourself with the rules and guidelines of the forum. We are a society based upon the philosophy of Harm Reduction. We are not overtly "pro-drug" or "anti-drug" here, although all are entitled to their opinions, we are here to keep people safe.
For this reason, we don't allow threads that essentially are asking how the user can get high. We will only direct you toward relative safety and not give you direct tips on how to get more fucked up. This would be contrary to the nature that we intend to exist in.
With that said, I can give you a quick tip. I don't know much, but I (unfortunately) know Methadone and Opioids as a whole like the back of my hand. Methadone has been a mainstay treatment for Opioid addiction for decades now. Why you ask? It's because it's a pretty effective medication in the management of addiction if dosed according to plan. At a dose of 120mg, a buzz from Opioids is firmly out of your reach. I'm sorry to say that, but you're a dog chasing the car down the street. You're not gonna catch it.
If you wish to return to the buzz of Opioids in favor of cleanliness and believe me, there would be no judgment from this guy if you did, then you must taper from the Methadone. Even at 30mg of regular dosing, a ten bag shot of Springfield, MA Heroin registered as a tickle to my system, while the runner who got it for me was drooling over his McDouble over a 2 bagger.
It just won't work. This is why you constantly hear of Methadone Maintenance patients turning to alternate substances i.e. Alcohol, Cocaine and most importantly, Benzodiazepines. By doing this, you're screwing yourself in the most extreme way. You would be better off without the Methadone and using Heroin, but my advice is to stay on the Methadone and investigate other means of attaining a buzz.
I'll add, that I've taken double and triple doses of Methadone at the 100mg dosing level. The most I ever felt was the strong urge to nap a few hours later...