A Google search led to an AI answer: "In the context of CB2 receptors, an antagonist is a substance that binds to the receptor and blocks or inhibits its normal function, preventing activation by endocannabinoids or other agonists". An antagonist, then, is a trigger.
One of the best "antagonist" substances is caryophyllene (β-Caryophyllene, beta-caryophyllene). The one I use is derived from oranges, pine, cloves, and sage. It is physician blended into a hemp seed flavored oil. The flavor is "orange creamsicle". Beta-Caryophyllene is also known as BCP. It is reported to have anti-inflammatory and anti-cancer properties. According to the National Institutes of Health (UK) may be prospective in the treatment of anxiety and depression. Significant findings suggested that BCP may hold clinical value for treating depression and anxiety disorders by addressing both behavioral and inflammatory responses to chronic stress.
BCP supports the immune system, relieves pain, reduces inflammation and can help to soothe and relax. I originally got it to help improve my wife's sleeping. The immediate benefit to her was pain relief in her hip. The sleeping has been more gradual in improving. And all with no sleep "fog". She now takes the CB2 softgels. Note that I am not an affiliate and gain nothing in providing this link to the Amazon storefront where I purchased from.
The products from Cannanda are all third-party tested. They are all well packaged with directions to use that are clear.
If you are into DIY home remedies, you might want to look into getting some caryophyllene and mix that into hemp seed oil. The flavor will be woodsy – but you can add some oil-based food flavorings to improve that. I personally like the orange creamsicle flavor in the Cannanda products and would likely look for the same if I did some DIY (and likely will).
Hemp seed oil has its own beneficial properties (without adding BCP). According to WebMD, "health benefits of hemp seed oil come from its high content of three polyunsaturated fatty acids: linoleic acid, alpha-linolenic acid, and gamma-linolenic acid. Additionally, its ratio of omega-6 (linoleic acid) to omega-3 (alpha-linolenic acid) fatty acids is 3:1. Experts agree that this 3:1 fatty acid ratio is ideal for health benefits." Health benefits include improvements in eczema, acne, psoriasis, and cradle cap. If you have high blood pressure, hemp seed oil can also lower your blood pressure. It will improve heart health by lowering total cholesterol especially the "bad" LDL. It will also reduce inflammation, and relieve symptoms of IBS, rheumatoid arthritis, and multiple sclerosis.
The ideal is about 2 tablespoons of hemp seed oil a day. 2 tablespoons = 30ml. It's easier to take in by the teaspoon. One teaspoon is about 5 ml, so you need to take six per day for the ideal. You can also use it (unflavored) in salads or sprinkled on other foods (like fish, etc).
DIY isn't for everyone. The benefits of triggering your CB2 receptors should be for everyone.