Random testing?

This may be slightly off topic, but who else would I ask. I'm under random DOT drug testing. I ussually quit smoking during my work season, but thats getting harder and harder to do. Weed is the only possible thing that would show up in my piss as I think I was pretty clean, but smoked a few hits over the weekend.
I found a plastic glue bottle and rinsed the shit out of it and found a lid that fits nice and tight. Went to my sons house before I had to go to work and had him piss in it for me.
I take it to work with me in the truck I drive and leave it on the defroster to keep it hot. That way I can stick it under my armpit and it should fall between 90-100 degrees. My question is how long will this piss be good? Does piss even go bad? How often should I have him replace it with fresh piss?
Usually when I take these test they give me the paperwork and I go to the hospital at the end of the day. They are pretty stupid at the hospital after hours and I think I could get away with almost anything. They do NOT watch me pee.
I should be getting laid off within the next month and then they pull me out of their testing pool. Cant wait to be stoned for about 3 months after that. Its bullshit that they invade your dick like this, but thats the federal way. Thanks for all replys, OD

Anyone please?

The Department of Transportation? I wouldn't fuck with them. I'm assuming you have your CDL and might drive a truck or a bus or some other kind of commercial vehicle, and the last thing you need is to get on the DOT's bad side. I have family that are involved in transportations/logistics, and they don't fuck around with weed at all. They don't take driving citations easily, and there are DOT sponsored enterprises that provide only drug testing services.

The fact you seem positive you will be getting laid off in the next month seems to be a good reason for you to put the pipe down for now. Because if you fuck up and test positive for anything between now and then, then any chances of you getting a job that requires a CDL is probably not going to happen.