Hi there,
Could use some advice about this. My DSD is six and is still not always wiping her bum properly. Is that pretty typical of six year olds?
I started noticing this after I properly moved in with DH and DSD 15 months ago (she'd just turned five), and began doing more of the household laundry - it's not always consistent, but when I tackle her clothes hamper, several pairs of her pants will have skid marks. On really bad days, it will look like a chocolate bar has melted in her underpants. Bleurgh.
We've tried talking about this with her several times. She says that "I'm trying, but I keep forgetting", and that "When I go to the bathroom, my teacher says to hurry up." We've assured her that her teacher does not mean, "Forget to wipe" when she says "Hurry up." We've tried to be patient about her doing the toilet at home. We purchase the kiddie wipes and leave them in her line of sight. We've warned her that if she doesn't wipe properly, the kids at school will think she's the smelly kid. We've told her about infections, and how not wiping properly can cause them. We've had her do her own laundry, so she can be more responsible. We've done the How To Talk So Kids Will Listen problem solving technique, where DSD suggested we write a poster of rules for the bathroom, to remind her to wipe (which she read out and taped to the door herself). On our end, my DH and I have been making more effort to make sure she has water to sip on and healthy meals to eat, and to bathe her every other night.
If DSD is having fun, e.g. if we are having a party and she is playing with her cousin, she is pretty much guaranteed not to take the time to wipe. The issue seems to be that she's so keen to get back to the action (or so keen to please the adult losing patience with her on the toilet), that she'll just hoik her pants up without finishing the job.
I don't know what else to do. Should I just ignore it and hope she gets over it? Maybe that is the best thing now? 
I'm really afraid she's going to get an infection if we do that, but I can't think of anything else that makes sense. I don't want to check her bottom every time she uses the toilet in our house - she's six and too big for it. Plus, we can't check her bottom (or expect her teacher to) while she is using the toilet at school. My DH insists DSD's been using the toilet since about aged two, so she's not a late bloomer in that sense.
Any suggestions?