Why did my mom want me to pee in a cup?

Do NOT do this!!!!!!!!!!!!!!!!!!!!!  It appears she needs to take a Drug Test before she can begin working; wants you to pee in the cup because she knows (due to her using weed) she will NOT pass the test.  DO NOT DO THIS!

Maybe she's subject to drug testing and she's a MJ smoker and needs a clean sample to submit secretly.

She knows you smokin' that good-good.

Any credible drug test will have mechanisms to assure the urine comes from the testee, not an acquaintance or proxy.  Typically this is done in a controlled environment (locked cabinet doors) with almost direct supervision.  If you are not the same gender as your mom, analysis of the urine can easily detect a counterfeit donor!

More likely, your mom wants to test if you are using drugs.

she really wanted a golden shower

Maybe she was thirsty.

If she came home from a job review, then it is likely that they informed her that there will be a drug test. The employer wants know if she has recently used drugs. Probably looking for illegal substances.

This could be based off something that happened, or some companies do random drug testing.

There are several common employer concerns related to substance use / abuse. One is that being under the influence of drugs could effect her job performance. Another is that impaired judgement could create a safety concern on the job site....especially if the company could be legally held responsible in any way.

Drug use, especially the choice to use illegal* substances, can be seen as an indication of the type of decisions are person makes. An indication of who they are as a person. Businesses want honest employees that work hard and benefit the business's interests.  Most want workers that don't get involved in anything illegal. It's less to worry about.

There's a few different ways to test for drugs. A lab can analyze a hair sample, a sample of saliva, or analyze a urine sample.

The most common, most available, and probably the cheapest is the urine test.

It would seem that she wants you to pee in a cup so that she can use your pee, instead of hers, for a drug test. This implies a belief that you* are not using drugs.

If she needs help to pass a drug test....probably means that she is worried she has something in her system that she doesn't want anyone to know about. Like maybe she's used drugs recently.

Some parents ask their kids to take drug tests to make sure they're sober, and not involved in anything potentially harmful (drugs / alcohol etc.)

What do you think is going on?

She is a druggie and needs some clean urine.

I guess she will be drug tested and wants to use your sample for the test.