adverb. Joyfully and wonderfully, if the joy and wonder were replaced by thongs.
Real citation: "Tough but tender these women's dressy thong sandals from Hot Kiss definitely have an attitude. Smooth patent upper in a thong style with a central metal ringsnap accents and metal spikes for an edge. Toe post thongfully lined interior. Cushioned footbed and a matching patent wrapped midsole. Smooth flat dress style outsole and a patent wrapped 2 inch just-right"
("Hot Kiss - Women's Shania," http://www.pricehunter.com/shoes/Hot-Kiss-Womens-Shania-2700.htm)
Made-up citation: "The Pope thongfully did something infallible, Vatican sources say."