A possible concise summary is:
Two friends, Unai and Amara, go to a party at Andiamo's house, where they meet many strange people and witness bizarre scenes. They escape from the police raid and end up at Unai's grandmother's house, where she offers them meatballs. Unai tries to seduce Amara, but his grandmother switches places with her in the dark and gropes him. They discover the deception and run away, while Unai's grandmother chases them.
Here are the key facts extracted from the text:
1. The speaker is Unai, and he is talking to someone named Andiamo.
2. Unai invites Andiamo to his apartment to show him something.
3. Unai and Andiamo go to the apartment on a motorcycle.
4. Unai mentions that he believes in communication and good manners.
5. Unai asks Andiamo if they are going to his house to engage in an erotic activity.
6. Unai shows Andiamo around his apartment, including a room he calls the "thinking room".
7. Andiamo comments that the room looks like a scene from an evil movie.
8. Unai mentions that he has a lot of industrial waste in the room.
9. Andiamo asks Unai about the bottles in the room, and Unai explains that they contain semen.
10. Unai says that he has a small penis, but he runs a lot.
11. Unai and Andiamo decide to play some music.
12. Unai invites some friends over, including a lawyer named Raúl.
13. Raúl brings some other people with him, including a woman who is very drunk and wants drugs.
14. The party gets out of hand, and the police arrive.
15. Unai tries to calm the situation down, but it escalates into chaos.
16. Unai and Amara (a woman who is with him) escape the party and go to a gas station.
17. Amara receives a phone call from someone named Francisco, who invites them to his house for dinner.
18. Unai and Amara go to Francisco's house, where they meet his grandmother.
19. Francisco's grandmother serves them meatballs, and Unai comments on how delicious they are.
20. After dinner, Unai and Amara go to a room with Francisco's grandmother, who encourages them to have sex.
21. Unai and Amara are uncomfortable with the situation, but they try to make the best of it.
22. The scene ends with Unai and Amara trying to escape from Francisco's grandmother, who is trying to seduce them.