Bodyglide is the recommendation you'd probably get from most people. It hasn't solved all my problems, because I tend to sweat through it at about the 10 mile mark, but it's worth a try.

Bodyglide is your friend.

Buy those blister bandages with the soft gel on the inside, these add some real sweet padding and stopped chaffing on all my long runs.

http://www.pharmacy2u.co.uk/compeed-blister-treatment-medium-p1576.html?utm_source=sfeed&utm_medium=google&utm_term=compeed-blister-treatment-medium&utm_campaign=main&gclid=CIiKlfiH3bICFUPHtAodwx8ArQ

I've been using runguard recently, to good results. I've only used it on 10 mile runs so far, and now I'm worried about "sweating through it" or it otherwise becoming ineffective. Before that, I taped up with neosporin soaked gauze and prayed the tape stuck. It often didn't, and caused more issues

The blister pad idea is stellar, I thank you!

Body glide (and powder - does not matter what kind) work for me. Lasted through 20 miler this weekend (and I did chafe 2 weeks ago on a shorter run)... be careful about switching up on bra's too. I have one style I really like but tried rotating in another that worked on short runs a couple of weeks ago and had issues!

BodyGlide actually makes a liquid powder, which I think is far superior than their solid stick. I have two pairs of shorts that cause me to chaffe, and all of the others are fine.

In order to prevent chaffing on the upper body's contact points - I now wear an Under Armour base layer, which is basically skin tight, and I haven't had the need to utilize any type of lubricant.

A HUGE shoutout for Aquaphor Healing Ointment (or as my kids now call it, butt chapstick...)