To the best of my knowledge, this theme was discovered by Rev. Noel Bonavia-Hunt (during the late 1940s - early 1950s) while he was compiling his well-known Research Pamphlets.* Two beautiful examples by Arthur R. Gooderson can be found in the PDB (P1030076) and YACPDB (206600). The basic idea is this:
Scheme (= 4+5 )
The key is played. White threatens mate by 2.Qe5#, leaving the bQ pinned by the wRa4. But Black can defeat this threat by 'cutting the tail' of what is actually a masked battery, prospectively unpinning the bQ indirectly - 1...Sb4. This constitutes the Tailcut Theme.
Question: If wRa4 were moved to b4, would 1...Sxb4 still be regarded as showing the Tailcut Theme (being a capture and not a line-closure)?