hot stuff 
noun [mass noun] informal
1A person or thing of outstanding quality or skill: he’s hot stuff at arithmetic...
- Buchan got a reputation - which would surely have horrified him - of being a writer of hot stuff.
- It doesn't seem to have occurred to the American Advertising Federation or its corporate sponsors that it is insulting to tell a group of students that, for minorities, they are hot stuff.
- Raising the chip to my anticipating lip, I braced myself for some hot stuff, but the burnt sienna dip, most likely whipped up on the premises, wasn't nearly as spiced up as it could have been.
1.1A sexually exciting person, film, book, etc. Jill was reputed to be hot stuff...
- The film had already received heaps of advance press, assuring decent ratings, but the TV suits apparently got cold feet about the hot stuff in the film (including a symphony of sexual shots early in the movie) and pulled the plug.
- And, two, just because she's hot stuff, it doesn't mean you aren't!
- And it's all pretty hot stuff, some of it deliciously erotic.