Suggests what occurs after「a thousand screwings」or「repeatedly bobbing head, screwings with erection」to be a PROMOTION, a RISE IN RANK among one's peers. Note that one thousand screwings by a service provider of short-term rentals in a brothel could be racked up in hardly no time at all, perhaps less than a year depending on the busy seasons, and would therefore enable sufficient experience/expertise as a MEASURED BOX (please pardon the vernacular there). See 昇 as「tonguing mouth promoted」likely for the same reasons.
「Erection head twisting, screwing.」.or,「in two hands」describes one process for RAISING, RISING the tool, a procedure common among anyone CAGED IN A PRISON CELL, either as an inmate jailbird or as a service provider chick owned by a shaman, both being caged or jailed 'birds' of different sorts, COOPED UP in CELLS ON A GRID.
「Repeated bobbing head」in「two hands」or「erection screwing」noting that the「repeat」element is seen on one side only, resulting in an action of LIFTING, RAISING up, or HOISTING contents from a larger quantity in a MEASURED BOX, and then leveling the commodity by sliding a strickle across the top of the box with the other hand, perhaps. A UNIT OF MEASURE for grain or other commodities, shaped in a SQUARE WOODEN BOX, with a volume of 1.8 liters, or roughly one-half gallon that is about the size of one chicken. This is the size measure for selling bottled alcoholic beverages in Japan, a rather large bottle normally requiring「two hands」for pouring that may result in「repeatedly bobbing heads.」
In China, this same element appears as 舛 and refers to birds kept in a coop, with each using a MEASURED BOX for nesting. Each box is measured to be nearly the same size as all the other boxes to avoid battles among the birds for the best boxes. CELL or GRID also refers to bird coops, as a wooden pole structure shaped as cells or a grid used for roosting. Birds compete every day and night to be raised in a position higher than the other birds:
「By instinct, chickens want to roost ('go to bed') in the highest point available, and be gathered together in a group for protection and warmth while they sleep. Your chickens will be happier animals if you play to their instincts when you are designing their living space. If you were to place multiple roosts inside your coop with some higher than others, they may fight to get the highest ('best') spots: to avoid this, you keep the roost at all the same level. …A chicken roost is a very simple board…or a wooden clothes rod like you would put in a closet, or even a thick tree branch that is about [2-3 inches in diameter].」
[ https://www.pet-chicken.com/why-chickens-need-a-roost/ 2014-09-29 ] Does sound similar to chick peers competing in a brothel, does in not?

External source definitions …excluding politically incorrect concepts and other meanings deemed offensive today; may include extended definitions, euphemisms, and mnemonics)
Chinese: to ascend; to rise in rank; to ascend; to rise to the rank of; to promote; to hoist; liter; measure for dry grain equal to one-tenth dou 斗
Japanese EDRDG: measuring box, 1.8 liter
Unihan extended: arise, go up; hoist; advance

Used within names (nanori)
のぼる