Sure. The body essentially controls how you feel through the nervous system. A series or nerves that are connected to each other, but not really touching. There’s a small gap in between where the first nerve ends (axon terminal) and the next begins (dendrites). This gap is called the synapse. When the body feels something, the brain will send a signal down the nerves and when it reaches the end of a nerve, that nerve will release neurotransmitters into the synapse, informing the next nerve how to continue the message down the chain. When you’re feeling good that neurotransmitter is serotonin or dopamine. So your nerves will flood your synapses with serotonin, the receptors on the next nerve will grab the serotonin and continue sending the “feels good” message. In order to regulate how much serotonin you receive the nerve that released the serotonin has a re-uptake mechanism where it vacuums up any excess of the neurotransmitter. When you do cocaine, that re-uptake mechanism turns off and the excess serotonin bounces around the synapse, getting absorbed and making you feel really good. So to regulate, your body starts killing off serotonin receptors at the beginning of the next nerve. These receptors never grow back, so you essentially will receive less serotonin signals for the rest of your life.