Brian Steinberg Senior TV Editor As is the case with most things related to toilet paper, this might get a little messy. An ad for Procter & Gamble’s Charmin toilet tissue ran adjacent last week on Peacock to a “Saturday Night Live” sketch making fun of the product’s long-running ad campaign that features blue bears talking about the benefits of keeping their posteriors clean, and in doing so, sparked a new round of online chatter about how involved advertisers can get in “SNL” content decisions. They typically can’t. NBC says the appearance of the ad next to the skit was “coincidental,” and not put in place at the request of Procter & Gamble, which has manufactured Charmin since acquiring the product in 1957. Procter, one of the nation’s largest TV advertisers, did not respond to a query seeking comment.