How to be the bad guy (and not feel really soft) to a teen?

[Toknowanything]

My 16-year-old is walking around the place like she owns the place and generally being lazy, not going to college, smoking weed a lot and she’s got a tattoo booked for her wrist next weekend.

I need to sit her down and have a chat with her but how I can I do it without feeling like the fun police?

I thought you had to be 18 for a tattoo?
If so I'd be ringing the place and telling them she is under age.

Yep you have to be 18 which I’ve told her and told her how it’s going to be somewhere dodgy as no where with a decent reputation will ink her. Ive just been told the city she’s going to get it done not the actual parlour or id be calling them up tomorrow/pressing chargers

You're the parent not a friend! Just do it amd good luck

Why are you worried about feeling like the fun police. Where is she getting the money for weed and tattoos? If she was mine I'd be really angry with her for not going to college and taking drugs and she'd know I was really angry with her. She would get no money from me. You're the parent, parent her

I confiscated the weed. I stopped giving her pocket money when she dropped out of college but she’s getting money from somewhere (probably the other side of the family). I can’t watch her when I’m at work. I didn’t know she had dropped out (essentially in her second week) until last week. I’ve told her she’s not going out with friends as she should be concentrating on going back to college/getting a job but I can’t watch her 24/7 when I’m at work myself.