Establish clear boundaries with your partner and the third person before engaging in any sexual activities. Make sure everyone is on the same page about what to expect and what is off-limits. 2. Respect each other’s comfort levels and don't pressure anyone into doing something they're not comfortable with. 3. Use protection! Even if you trust everyone involved, it's best practice to use condoms or dental dams for each new partner to prevent any potential health risks or unwanted pregnancies.