Need to dig myself a deep hole and bury myself in it!
On a Skype call with two colleagues about a presentation we are putting together as a team. We are reviewing another colleague's section (which massively impacts my area and the entire project) and he has got some fundamental details the wrong way round. I have discussed this with him earlier in the project, so I know he knows how it should be. Just as I say 'I am going to speak bluntly here, he should know which way round this should be by now, we have discussed it before', (with a bit more project specific detail) because I am frustrated at this not being the first time, we have already spent a load of time correcting his spelling etc, said colleague speaks up 'hello, I am here'. He has joined early for a subsequent call and clearly heard me. 
I am very fond of this colleague because he is a kind and fun person to work with, but he has no capacity for detail. He is one of those people who expects to be able to do a basic job and then someone else will finish it off to the required standard. And much as I like him, I shouldn't have to keep doing it. But that is no excuse for being unprofessional and speaking badly of him. I have never ever done something like this before and I am acutely embarrassed.
Argh! Tell me it is going to be ok when I have a 1:1 with him tomorrow to finish off updating his section. 