What exactly was Ian Anderson's infamous 'anal intruder'?

Ian Anderson of Jethro Tull is associated with a notorious “anal intruder” gag included in the band’s folk-rock catalog, according to Prog magazine. The story traces the item to Dave Pegg, Fairport Convention’s bassist, who reportedly bought the dildo as a joke during the band’s electronic era, around a 29 September 1984 show at Festhalle Frankfurt. Anderson said it came from Dr Müller’s sex shop in Frankfurt airport, with a label reading “anal intruder.” Drummer Doane Perry reportedly became the target most nights: the toy was lowered on a fishing line during his solos, thrown into a backstage wastebasket, and then repeated the next show by Anderson’s group. The store still exists after Frankfurt airport redevelopment.