I usually book an hour punt with plenty of 69 before we get to the main action, a month or so back one SP pulled out the lube after 10 minutes of oral and being wet through and definitely not needing it, perhaps it's a nervous thing, I'm sure after punt after punt, day after day it's harder to get into the same spirit they did as a teenager behind the bike sheds for the first time with big Eric from the local factory who they'd lusted after for years, and concerned that they may bodily lose interest even if they're physically giving it the full beans but are mentally thinking about what's for tea.
I think generally they do a decent job of pretending they're enjoying themselves some times that interest is hard to fake though.