Fear of being punised:  Fear of being punished by your friend, fear of being punished if you do something that you regret at the party.

What will you get out of it?: If you do something wrong or innapropriate at the party, you will have a bad reputaion. Maybe a good time.

To be liked and to be gained approval: To be liked by your crush.

Something or someone which has been accepted asa higher authority: Your parents would be telling you not to go to the party because it isn't a safe environment to be around. You could get hurt and you shouldnt be putting yourself "out there"

Conscience of society or the group about the issue: If you do something wrong at the party, the word will spread and you will have a bad reputaion. The group would think that you are a chicken and that you do not what to try anyting new.

Demand for justice:  Your choice may not be fair for everyone but at least you will feel like you have done the right thing

 If they are very religious, then they would strictly follow the Catechisms

 "Human life is sacred because from its beginning it involves the creative
action of God and it remains for ever in a special relationship with the
Creator, who is its sole end. God alone is the Lord of life from its beginning
until its end: no one can under any circumstance claim for himself the right
directly to destroy an innocent human being."

The Old Testament attests that God is the source of all truth. His Word is
truth. His Law is truth. His "faithfulness endures to all generations."

They close the sexual act to the gift of life. They do not proceed from a
genuine affective and sexual complementarity. Under no circumstances can they be
approved..