Wait, he just says, "Yes, Ma'am" and buys everything?

Or I should say the nightmares.  The Girhippo would constantly complain about lost socks at our house;  how would she know?  she's such a slob there was probably socks from months past hidden under piles of crap.  She literally would send OSS on search missions in our house for the Lost socks

I would buy 1 bag if socks and give them one pair each to wear. They can take back the one pair to mommys house. T-shirts? Check out the clearance rack. That $3 t shirt is just as worthy as a $15 t-shirt. Jeans? Goodwill. Tell DH the limit is $10 per child per weekend. 

I get that DH wants his kids to have clothes and both parents shouldn't get shitty about dressing their own children. But the situation is rediculous. And he won't be letting his kids go without. He should be teaching them that adults have to plan and budget. In fact he can have this talk with them. 

Also DH does not have to buy anything. He should send her a letter back to BM telling her that he doesn't have time this weekend and he will leave it up to her Or he can ask for half the cost of the shopping spree to be pre-piad. She can send him $100 cash and he will send her copies of reciepts and any change out of her $100.

The other option is to get to the note first and destroy it. Put it down the garbage disposal. I agree with you though that this bleeding you dry has to stop.

O.M.G. So he's basically paying about $1500+ in CS every month. Lt Dad, maybe he needs a kick in the arse to dislodge his head...

Your DH is a pushover. You are going to need someone else to call him out on spending so much so often for him to have that epiphany that he is overspending and BM is bamboozeling him. Depending on your relationship with his mother, she would be a good source to use for this. Sometimes when my DH wants to run out and buy something ridicuous (speed bike) I will schedule a dinner at his mom and bring it up in front of her because I know she will tell him how absolutely stupid it is for a grown ass man with two children to buy a single person, dangerous motor bike. Maybe your mother in law or father in law or someone else that. he holds value in their opinion and have them say it out loud that he shouldn't be spending that much money each week on socks, etc. Then he will stew on it for a bit then act like it was his idea so go along with it and fully back him up. 

IIRC, dad is responsible for ALL extras, no?"

The BM in our case would always send my SSs in socks with holes in them with their heels or a couple toes sticking out. Or, the SSs would be in pajamas when picked up mid-day on Christmas Eve, knowing we were going to church and my DH's mother's house for a family celebration. We constantly had to buy them things EOW that BM should have bought with CS. Then she'd send them with hair so long it looked AWFUL, wanting DH to take them to get haircuts. All of this was more $ on top of the $1200 CS BM got per month, plus gas and tolls it cost my DH for the 4 hour round-trip drive to get SSs on Friday and take them back on Sunday. We easily paid out $1500-$1600 on a regular month, of course, not including birthday months, Christmas or vacation, and that was a LOT of money to us back then. Thinking back on it makes me angry but gives me great satisfaction that the days of BM having her claws in DH's money are long gone (CS ended several years ago) and we give SSs money directly when we want to, and BM has to finance all her own expenditures. I spent many years counting down the months and wish I could have just rolled with it, but I know how frustrating it is. 

My head almost popped off.....LD, stopppppppppppppppppp

You and dh must stop buying the kids anything unless everything you buy is STAYING at your place.

BM is ordered by the court to receive a hefty amount of CS.  IF your husband continues this he will have two court order payments. BM's and yours.

I have zero empathy for ncp who pay out the rear in cs then, turn around and buy things the lazy bm should. NO...nope nope.

Buy all things for your house only...wash stuff the kids came in and they wear it back to moms.

Problem solved.

Hey one more thing....all of you could request modification of child custody because BM's are "not clothing the children'....

Custody has been changed because of stuff like this. You could word it that BM makes the children wear tattered clothing, not weather appropriate and does not wash clothing.

Forms of neglect. Just saying.

Just start asking your DH for a bunch of ridiculous random things- Hey DH, can we get a pony and keep it in the bathtub?... No? What about buying me a Porsche convertible?...No?

“Not everyone gets everything they ask for, and it seems you know the word “no”, so How about trying it out on your crazy ex?”