「Rod within spread legs orifice」suggests that after vaginally deflowering a virginal female, the orifice becomes ALIKE, EQUAL, ALL THE SAME as that of other vaginally deflowered females.
Giving birth or laying eggs as with a post-natal birth canal, and thereby becoming ALIKE, much the SAME shape and EQUAL size internally as most any other such「widened orifice」possessed by birds, or other animals, or other people with a history of producing offspring…jumbo-sized chicken eggs are laid by the oldest hens with the loosest cloacas, multigravida, multiparous;…note that only birds are bipedal as are humans in regard to the「spread legs」element (see 姻 meaning 'marriage' as a 'female with enlarged orifice' caused by childbirth).
Prior to the days of episiotomies, after giving birth the vaginal canal would stretch sufficiently that sex with any such vagina all felt the SAME, ALIKE, as would any old hen's cloaca, causing bonobo-like human males to seek tight and「small orifices as booty」(see 尚) and may be why ewes, ass holes, and virgins were so praiseworthy and recommendable, affable and habit forming, or prized and esteemed (the meanings, respectively), and why adjustable no-longer-integrated feet became so popular (ㄅ, the outer element of this glyph) depicts a「widened orifice between spread legs」as in 仝 (a non-JIS glyph),「person's flesh seam」with SAME, ALIKE as the meaning. As Zaph0d says,「Turn 'em upside down, and they all look the same」that goes for both women and men, all with that SAME orifice which is ALIKE among any sexual variant, 仝. Something akin to「If you've seen two, you seen them all.」
And of course,「reciprocal rod motions」with「asshole」refers to the above.「Reciprocal rod motions with management and administration」clearly describes a common feature of humans as being THE SAME, with both females and males ALIKE using at least one hand for「managing rod motions」as that need arises when sex rears its ugly head (the root of the English word 'manage' refers to the use of one's hands: manu).
「Vertical motion, rod」with「government official, or, an anus」arguably might all be just about ALIKE, much the SAME and EQUAL, regardless of the amount of work, or use. The anus does not always stretch during parturition as does the vagina, although some flesh tearing was fairly common in the old days (see 曾 and 曽).
As「array, line up of vaginas」the elements suggest a common feature of females, hence not one to be given undue consideration since they are「all alike」in some ways, which may have led to the male proverb equating women to buses with respect to the frequency of the next one's arrival.
And lastly, a special inanimate「rod」(not a living thing)「in vagina」will always feel the SAME each time it is applied, CHANGELESS and dependable, never flaccid nor disrespectful.

External source definitions …excluding politically incorrect concepts and other meanings deemed offensive today; may include extended definitions, euphemisms, and mnemonics)
Chinese: see 衚衕|胡同; like; same; similar; together; alike; with
Japanese EDRDG: same, agree, equal
Unihan extended: same, similar; together with