The Harleep scene is a fully animated sexual encounter where the player character cannot give consent. Harleep uses mind altering magic to influence the player character throughout the scene. The player also is not told beforehand of the permanent negative consequences of the encounter, so there isn't informed consent.
I strongly dislike how this scene is at some points played for laughs (for example, the review of the player's body you can receive in the epilogue), while also being explicitly compared to the centuries of abuse Astarion suffered. Treating SA as a joke disgusts me.