What is the risk of being affected by alcohol, drugs, and medications when doing watersports with someone who is using any of these?
Many chemical elements are not completely broken down in the urine and can be passed on to someone else through urine (ingested or otherwise absorbed). Talking with your pissing partner about their drug use will be particularly important if you do not use the same drugs as they do, or are not accustomed to them. You may want to come to some agreement about what you are willing to “take” during water play in terms of recreational drugs, and refrain from swallowing if your partner is on prescription medications.
To your health,