Tingy was the name given to the blanket owned by Manny in The Last Straw (also in Diary of a Wimpy Kid: Dog Days (film)). According to Greg, Tingy was blue blanket that Susan made for Manny on his first birthday—Manny was apparently so attached to it that he would take it everywhere with him and he wouldn't even let his Mom take it from him so she could wash it. Because of that, the blanket ended up becoming just some strings of yarn stuck together with raisins and boogers by the time Manny turned two, which Greg thinks is when Manny started calling it "Tingy." Eventually, Frank ended up throwing it away (though in Frank's defense, he didn't realize what it was). When Manny started freaking out when he couldn't find Tingy, Frank explained that he accidentally threw it away—Manny was able to get back at him by using his Civil War Battlefield as a playset and also started taking his anger out on everyone else and called Greg "Ploopy".
When it was Seth Snella's half birthday, Susan knitted a blanket just like Tingy, Manny went to the place where the presents were kept and while digging through them, he found the family's present and opened it and found a blanket and he thought it was a "brand new" Tingy for him, but when Greg came to take it, Manny chucked it on the top of the branch.