If you're looking to have a successful threesome, it's important to start by doing your research and setting clear expectations. Make sure all parties involved are comfortable with the situation, and have an open dialog about desires, boundaries, and any potential risks beforehand. All participants should be aware of safe sex practices and use protection during sexual activities. Communication is key throughout the entire experience - make sure everyone feels respected and heard. It's also important that everyone feels safe to express their feelings before, during, and after the threesome.