Painting basement wall with obstruction
Take a brush or putty knife or trowel or slab of cardboard or whatever you have on hand and slather the material in there. Get it thoroughly covered so that your primary objective--sealing the wall--is accomplished. 

Then wrap a large rag around your hand and dab off the extra. Really you're just trying to prevent runs and create a texture that comes close to the rest of it. There's no science involved at all.