Well, according to my recent and wonderful journey through meditation, I feel they are the exact same process, if done with a knowing and understanding mindset. In my own words: meditation is just a state of existing, without any worries about past, present or the future. You just exist as an individual in the single instant of your life. Nothing is more important or less important than that single instant. And during a sexual experience, you are trying to obtain the same feeling. You want to just exist, with your partner in this case, so much so that all else melts away and only the single instant matters now, there is no time, there is no 'reality' in a sense. You are the only existence in the Universe during those moments, and that is all the matters and is important to you during the most meditative moments.
Again, this is all just from an understanding I have very recently discovered through meditation myself(as in just this very night myself, I submitted a thread a few hours ago.. it's waiting for mod approval? to be seen, but I would also encourage you read that when it becomes visible to members and hope it can help as well), so don't take me as an expert or some special guide on this issue. I would implore you to continue searching and find the answer yourself, as what I say is in no way enough knowledge to fully comprehend or understand what you can obtain through your own personal experience an infinately similar experience.
I wish you the best

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