I just got this for my paladin and had 0 skill in both Begging and Alcohol Tolerance but noticed I still had a rough defiant charm on my lvl 87 Pally so decided to skill them up.
I went to Crescent Reach and had my Bard in the group singing "Soothing Psalm of the Sunrise" lv 57 spell from the spell seller in Lceanium to lower drunkenness, and just begged off librarian Hemfar and drank Brandy from the nearby bartender i bought 1000 and had 400 left when i got to 200 skill in AT and begging was skilling up pretty much at the same speed.
I didn't time it but it was less than 2 hours total to max out the charms stats.
If you immediately click off the spell icon for the bard song every time it appears, it goes faster.
I think because the effect triggers at the end of the spell effect. I think when the bard song overrides the last version and updates the time it triggers too but clicking it gave me something to do and it felt like it was going faster.
Hope this helps speed up getting your skills up, good luck.