Add the bacon and cook until crispy, stirring often, about 5 to 7 minutes.
Remove the bacon to a paper towel-lined plate to drain.
Discard all but 2 tablespoons of the bacon grease.
To the hot grease, add the garlic. Cook for 1-2 minutes, stirring constantly, until fragrant.
In a small bowl stir together the flour and dry ground mustard. Add the flour to the pot and stir to combine. Cook for 1 minute.
Pour in the beer and stir. Cook for 2 minutes.
Add the cream cheese and cook until melted, stirring often to help break down the cheese. The beer will thicken up when you add the cheese, that's a good thing. You'll want to use your spoon to smush the cream cheese and little and get it incorporated into the sauce.
Add the cheddar and Colby-jack cheeses. Stir to combine until the cheeses have melted and the sauce is thick and smooth, about 5-8 minutes.
Season with salt and pepper to taste. Add the hot sauce and stir to combine.
Add almost all of the bacon into the dip, saving a little for garnish. Stir to incorporate the bacon.
Transfer to a serving bowl (or a crock pot set on warm), sprinkle the reserved bacon on top. Serve immediately with soft or hard pretzels.
Notes
This dip is best warm and it will start to set up once you put it in a bowl. I highly recommend keeping it a crock pot set on warm if you serving it at a party.I made some homemade pretzel bites to along with this dip, but store bought (hard) pretzels go great too!