Ok, here's where we start. Get yourself a 1/2 gallon size pump up sprayer. Loosen ring connecting spray head hosing. Save in case your wife finds out what you've done and makes you put her rose sprayer back in original condition.
Now that you've loosened that pesky ring, cut the hose off if you can't get it to slip off. Then slit it down the side and peel it off. Set the original hose aside in case you ever want to reuse this thing as a sprayer. If so, remember to clean it real well first. You can use a late model GM master cylinder cap. You have to take 5 seconds to modify it but it works fine after that. What you will find when you open the package is that the GM piece has a little groove cut in the underside of it to relieve pressure!?! I don't know what the hell that's about, but take some black (or whatever) RTV and using a scrap of the original packaging, smear the groove full of RTV and let it cure for a bit.
While at Pep Boys buying the cap, get a 1/4" hose fitting with a threaded base and associated brass nut. Drill a whole and enlarge to the size of the hose fitting. Screw that baby in there and secure from the back (see next pic) with the brass nut. Connect 6 feet (or whatever you feel like) of 1/4" poly hose to the sprayer and cap, and secure it with hose clamps.
Here's how you use it. Pour in 1 to 2 liters of fresh brake fluid and after sucking old brake fluid out of master cylinder with your wife's best turkey baster, refill and screw the cap on. Pump it up to pressurize and start bleeding brakes. After you're done, loosen main sprayer cap slowly to relieve pressure. Suck out or fill up master cylinder to full level line and reinstall factory cap and sensor.