You are open to being bisexual. You define your gender orientation as straight but you are open to having a bisexual experience. One step farther then bi-curious but one step back from being bisexual. The term is to imply that you aren't looking for a same sex experience but open to it if it were to be presented.
I don't normally sleep with men but in your case, I'm bi-open.

Alan: Is Beth leaving with that woman? I thought she was straight.

Rick: She is, but she is bi-open.

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