Yea I get that but you made it sound like they really enjoy it cause some go deep. I can confidently say 99% of WLs don't enjoy doing it. If they're sticking their tongue deep into your arse it's just their dedication to their job.
I mean unless everyone's arse tastes like lollipops and skittles I'm fairly certain not many WLs would wake up in the morning and be like, "Oh boy! I sure look forward to tasting some arses today!"