Busted

I live at home with my parents and mother's mother 65 and I'm a nerd best description short and to the point. My parents are both very career driven people and have hired a housekeeper 57 to look after the house and cook the meals. She an undocumented immigrant and I found out and blackmailed her into letting me fuck her. During one of the times, I was fucking her. My grandmother came home earlier than I expected and saw fucking the housekeeper. Didn't say anything or make a scene, she just waited until the Saturday morning the housekeeper goes shopping and my parents were busy as usual for them. My grandmother approached me and straight out asked how long, have I been fucking the housekeeper. I was shocked that she knew and told the truth about a month ever since I'd discovered she was undocumented. You blackmailed her into giving you sex she said, and I just nodded. Smart boy was her response, I looked at her and she added now I know you'll have to fuck me to keep it quiet. I just looked at her in shock and she added yes, I'm blackmailing you now. I had no choice and so I started fucking my grandmother, a month later the housekeeper left to return home. She had saved all her wages and had enough for what she wanted to do. A new housekeeper and I had no interest in her sexually, anyway I had my grandmother and I'm regularly doing her whenever she wants.