Looked up on Moeoh's website, the pamphlet/booklet is a special feature included with the magazine titled おとなの萌王 僕の彼女の下着が×××♥
(Adult Moeoh: My Girlfriend's Underwear is *
♥). A collection of artists draw beautiful women showing you, their boyfriend, their special underwear.
The sample drawings online are all sexy pin-up style, but the artist listing shows Barasui's at the end, so I'm guess his is some kind of silly punchline.