What was your conversation with your friend, God? Sin is not the things we do. Sin is why we do things. God is our friend and our acts are consistent with this or not. If you don’t know if it is a sin than it is kind of hard to imagine that you were trying to hurt your friendship.
This is… not quite right. Sin is an action, or a decision to act.
In order for something to be a mortal sin, three criteria must be must:
#1: It must be grave matter. #2: The person must be aware that it’s a sin. #3: The person must enter into the act willingly.
It sounds like you’re on the cusp, and definitely placing yourself in a near occasion of sin, but as long as you didn’t actively lust after the woman or objectify her, then I think you’re alright.
With that said, if you’re concerned about it, then go to confession. It’s not like there’s a limited number of times we can go, and it’s not like it’s any less effective the more often we use it; quite the opposite actually. ^^
I have posted several times before on CAF that I worked in a movie theater for a while and learned that every ticket sold was a vote for more of the same. It only makes sense that they count viewership to maximize their investment.
I don’t know how the various video producers make their money, but I’m sure they count their viewers as well. So you have cast a vote without being able to retract it. At least my theater had a policy of refunding the ticket price if you didn’t like the movie, but not after it was past the 20 minute mark.
You are obviously sensitive to this issue, so I would advise that you avoid them in the future so as not to encourage more of the same.
“Curious”, you say. Yes, that’s a sin. Sinful curiosity is when one pursues knowledge of a thing which is sinful, whether it is intrinsically sinful or it is sinful in the circumstances in which it is presented.
In the example you gave, the woman in bikini was dancing in a way directly intended to incite lust in the viewers. Even if you believe that you didn’t have “lustful thoughts” about her, that doesn’t mean it wasn’t wrong to watch the video.
You participated in the woman’s sin by watching her.
You showed some degree of lustful interest by “[looking] at her sexy body” with “curiosity”.
You satisfied sinful curiosity by seeking knowledge of “the other scenes” and “what she [was] gonna do”.
You willfully allowed yourself to be in a fairly dangerous occasion of sin.
For all of these reasons, yes, I think that it was a sin. I cannot determine whether it was mortal or venial; only you can do that. However, the sin itself was grave matter, and you should definitely confess this sin as soon as possible, with all of the detail that you did in this post.