Give scientific reasons: When a male is sexually excited,the epididymis wall shrinks/contracts.

(N/A) The epididymis is a $6 \ m$ long,highly coiled structure that serves as a temporary storage site for immature sperm. During their stay in the epididymis,sperm cells undergo maturation and acquire the capacity for motility (swimming).
When a male experiences sexual excitement,the smooth muscle walls of the epididymis contract. This contraction facilitates the transport of mature sperm cells from the epididymis into the vas deferens,moving them toward the ejaculatory duct.