Well, I suppose in theory two people could both use the same well planned final method, which they both do at the same time, and before that they could hang out and play around, etc, within reason, although getting excessively drunk doesn't sound like a good idea at all....
If someone were to use this approach then they would probably be wise to ensure that the final method used is highly reliable....
As always, whatever you decide to do, I would give careful thought to it, to be sure it's really what you want to do.....