New splice fitting

Oops.. new "splice fitting".. not spice.... Need to cut into the main stack and install a "Y"... I don't have any "slack" to move the stack up or down. I don't want to install a Fernco... Yet can't find a coupling (is "no hub" the proper term?) - that will slide up the existing pipe while I make my splice and then slide down to cover the jont. Is there such an animal...?? Specialty plumbing shop rather than the big box??

A no-hub coupling can be rolled up and then rolled down.
They are used all the time in a stack to insert a fitting or section of pipe.