I had a similar issue recently and during one of my many afternoons dicking around on the internet to avoid work I actually found a solution that worked surpris

I had a similar issue recently and during one of my many afternoons dicking around on the internet to avoid work I actually found a solution that worked surprisingly well: FocusMate.com It's kind of like chat roulette (before it got weird) for study buddies. I'll admit the premise is a bit odd butt don't knock it until you've tried it. Essentially, you're paired with a random partner for a 50 minute mostly-silent video chat. You spend the first minute or two saying a quick hello and each definitively stating what you're going to accomplish in the hour and then you get to work (separately - they're very clear it's not for collaboration). When time is up you both report back on whether you did what you set out to do. And while you get to work the corner of your screen has a little live stream of your partner diligently working. Not only does it help keep me "accountable" and working pretty efficiently for the full 50 minutes but it's also made me so much better/more realistic about estimating what can be accomplished in that time.