I’ve had a few experiences in the past. These days is getting more difficult to find a legit SD though. The important thing is: don’t let them exploit you and ask for an adequate allowance. If they say “I don’t want this to feel transactional, I’ll help you every now and then” don’t fall in the trap! They’ll get what they want from you and then disappear once you start to ask for something more substantial than a t-shirt from H&M. One trick that I use: I say my previous daddy (or my best mate’s SD) used to give me xx, I expect something similar. If he doesn’t like to handle cash you can set up a Bitcoin wallet and get paid in Bitcoins or ask him to buy you a small box of choc or a nice Card and hide the money inside so it doesn’t feel “transactional” (spoiler: most of the times it’s just an excuse for not paying!!)
Again: say your previous daddy used to do like this so you expect the same