Preheat oven to 400°F. Line a large rimmed baking sheet with aluminum foil; set an oven safe wire rack inside baking sheet.

Cut bacon crosswise into halves or thirds as needed to create 28 shorter strips. Place bacon in a single layer on the prepared baking sheet. Bake the bacon until fat is rendered and bacon is beginning to brown, 15 to 20 minutes. Set bacon aside. Remove and discard aluminum foil. Line baking sheet with parchment paper and set aside. Reduce oven temperature to 375°F.

Unroll crescent rolls on a cutting board and separate along perforated lines into 8 triangles. Cut into 28 skinny triangles; set aside. Slice each cheese slice into 7 equal sized strips of cheese, place 1 cheese slice on top of each dough strip; set aside.

Working one at a time, roll each smoked sausage in 1 piece of par-cooked bacon. Place on top of the wide base of 1 skinny dough triangle. Roll sausage toward pointed end of triangle, allowing dough to overlap and wrap around sausage. Place in even layer, point-side down, on prepared baking sheet. Repeat with remaining bacon, smoked sausages, and cheese-topped dough triangles.

Whisk together egg and 1 tablespoon water in a small bowl until combined. Brush wrapped smoked sausages with egg wash. Sprinkle evenly with everything bagel seasoning.

Bake at 375°F until dough is puffed and golden brown, 15 to 20 minutes. Serve immediately with mustard.