I don't get this... I don't let anyone sit on my arse, ever. If someone does get too close, in the overtaking lane, when I'm looking to overtake someone in a queue, I pull over. It's their problem, and I'm not going to be a part of it. I only sit on the arse of others when they do not pull over for no reason (actually, generally I undertake them, carefully).
I don't drive _that_ fast... generally about 80 when cruising in the UK, which is technically illegal, but what loads of other people do, and police won't do you for it (most of the time).
Seriously, people, if someone is sitting on your arse... pull over. Don't complain about it... they're more likely to die than you. You lose nothing.