If you are referring to: "Don't blame it on sunshine, Don't
blame it on moonlight, Don't blame it on good times". Then the song
you are after is: Blame it on the Boogie, by The Jackson Five.
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Both of you
If it's consentual, then you're both to blame, or neither is to
blame, depending on the circumstances. In other words, the blame or
non-blame is equal for both of you.