「Repeated head bobbing on rod one time and time again repeatedly, with stretched crotch skin」suggesting the steps up the trail of stretched crotch skin, advancing from one level of service provider to the next, and the next, and so on, that describes a STAGE OF PROGRESS of the climb, TIER, STEP up to a higher and higher GRADE, RANK (and billable timeslice for those matters), a「battle for the woody rod」that occurs within harems and love shrines among jealous peers in a group.
　「Repeated battles among internal divisions of stretched crotch skin」describes jealous concubines in a harem figuratively stabbing one another in the back (or, elsewhere) to get top ranking for themselves, not so unlike working for a service-providing enterprise anywhere today with numerous employees. If so, then a reversed 斗 glyph was used to form part of the left element.
　Given external source meanings suggest 'how long are your [foot-binding] cloths?' and 'length of service time' with 'textual explanations or descriptions' at each stage as a written record of the reviewer's comments, similar to an employee evaluation on a regular basis (see 叙), euphemistic references to concubine and service provider seniority, rank, and pecking order as in the order of being 'peckered' [sic] by the lord, literally.
　Alternatively, some suggest perhaps the set of steps of a trail up and down a terraced slope covered with irrigated paddies, and if so, the right element「stretched skin of crotch」depicts the motions and action of stepping up extending one's leg and stretching the skin of one's crotch in order to do so. Each new step is a STAGE OF PROGRESS of the climb, TIER, STEP up to a higher and higher GRADE, RANK, and so on. Or, depicts the process of constructing a stepped path or set of stairs up a terraced slope, but this explanation ignores other given meanings.

Modern definitions (that generally disregard history) …excluding politically incorrect concepts and other meanings deemed offensive today; may list only pigeonholed definitions, euphemisms, or meaningless mnemonics)
Chinese: paragraph; section; segment; stage (of a process); classifier for stories, periods of time, lengths of thread etc
Japanese: variable measure of fabric, for kimonos: at least 10 m in length, for haori: at least 7.27 m in length, for other clothes: at least 6.06 m in length, 300 tsubo, six ken, step, stair, steps, stitches, columns, grade, rank, level, counter for breaks in written language, gradually, by degrees, stairs, staircase, terrace, programme, plans, arrangements
Unihan extended: section, piece, division
EDRDG: grade; steps; stairs