Sticky strings

I am trying to figure out a solution to the stickiness on my ubass strings and have not found much good info yet. I have the stretchy polyurethane stings that came with it. I like the way they sound, but the E and A strings (especially) are sticky and make it difficult to slide or even move my hand freely to the next note. Also, they're not consistently sticky across all the frets, and the D and G strings feel much less sticky, which I find strange (perhaps simply due to the degree of surface area). Is there a solution to this or do I need to just accept that this is how these strings are? I have tried making my fingertips oily by rubbing my nose (though this may not by oily enough) and have tried water on my fingertips (but this has a very short-lived effect and I'm not keen on introducing water to my instrument). I am considering switching to flat-wound metal strings because of this. Also, does anyone else find the poly strings annoying to tune?