( ( Right ( before ejaculation ) ) ( , ( ( ( ( fluid ( from ( ( ( the ( prostate gland ) ) and ) ( seminal vesicles ) ) ) ) mix ) ( with ( ( the sperm ) ( in ( the ejaculatory ) ) ) ) ) ( ( ducts ( to ( form ( ( semen , ) ( which ( is ( ( forced ( through ( the urethra ) ) ) ( during orgasm ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (ADVP (RB Right) (PP (IN before) (NP (NN ejaculation)))) (, ,) (NP (NP (ADJP (JJ fluid) (PP (IN from) (NP (NP (DT the) (NN prostate) (NN gland)) (CC and) (NP (JJ seminal) (NNS vesicles))))) (NN mix)) (PP (IN with) (NP (NP (DT the) (NN sperm)) (PP (IN in) (NP (DT the) (NN ejaculatory)))))) (VP (VBZ ducts) (S (VP (TO to) (VP (VB form) (NP (NP (NN semen)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (VP (VBN forced) (PP (IN through) (NP (DT the) (NN urethra))) (PP (IN during) (NP (NN orgasm)))))))))))) (. .)))
Right before ejaculation, fluid from the prostate gland and seminal vesicles mix with the sperm in the ejaculatory ducts to form semen, which is forced through the urethra during orgasm.
(ROOT (S (NP (DT The) (NN prostate) (NN gland)) (VP (VBZ secretes) (NP (NP (DT a) (NN fluid)) (SBAR (WHNP (WDT that)) (S (VP (VBZ mixes) (PP (IN with) (NP (NN sperm))) (S (VP (TO to) (VP (VB help) (NP (NN form) (NN semen)))))))))) (. .)))