Just to be clear up front that I like Fleetwod Mac, and I subscribe to the view that 'Rumours' remains possibly the best album ever made and certainly in the top 10 albums ever; however...

'Big Love' I've always found to be tawdry and somewhat embarrassing

I note that no-one has yet referred to the all-time classic that is 'Diane' (not!!)

Used to take it and go clubbing. Would have been mortified if I had soiled myself. Must have been taking rubbish gear it seems

I think you should be ok. Usually by the time you've got round to blowing coke up your jacksie because your nose is so f**ked, you've probably not eaten in a week, and are so amped up, your sphincter is smaller than a full stop.

Also, I think its probably 'via somekind of straw', inserted into the anus, so it wouldn't affect the sphincter - You could I guess dab it onto the anus, by the effect would be limited - Really you want to get that powder into the colon and absorbed through the colonic wall.

Allegedly

There is a one off concert in London in late October featuring Doobie Brothers and Steely Dan and they must have a combined age in excess of 500

Finally an expert. Is it possible to mix cocaine into a sort of paste with some kind of petroleum based product and then insert it into the ring piece using the middle finger? Or would that not get you high?

Guessing the petroleum would inhibit it's absorption would it not?

Quick bit of wiki (this is willos area of expertise so perhaps he will be a long shortly to confirm my findings) is that cocaine can be mixed with water in a soluble solution and using some kind of squirter / douche be squirted into the anus that way.