why does semen smell the way it does?

i have noticed semen has two scents.

the first scent is the ocean breeze scent that you smell when you first ejaculate. sometimes it smells like bleach too

the second is when its been sitting around for a while.. when it begins to smell like squid or rotting seafood.

i have no problem with the first kind, but the second one is truly annoying.
why does semen start to smell like that, and how can i prevent it or reduce the stench?

Putrescine, Cadaverine, Spermine and Spermidine

Putrescine, Cadaverine, Spermine and Spermidine

Putrescine originates in putrefying and rotting flesh, and is quite literally, the smell of death. It is one of the breakdown products of some of the amino-acids found in animals, including humans. Although the molecule is a poisonous solid, as flesh decays the vapour pressure of the putrescine it contains becomes sufficiently large to allow its disgusting odour to be detected. It is usually accompanied by cadaverine (named after the cadavers that give rise to it), a poisonous syrupy liquid with an equally disgusting smell. Putrescine and cadaverine also contribute towards the smells of some living processes. Since they are both poisonous, the body normally excretes them in whatever way is quickest and most convenient. For example, the odour of bad breath and urine are 'enriched' by the presence of these molecules, as is the 'fishy' smell of the discharge from the female medical condition bacterial vaginosis. Putrescine and cadaverine also contribute to the distinctive smell of semen, which also contains the related molecules spermine and spermidine.

http://www.chm.bris.ac.uk/sillymolecules/sillymols.htm

thread over.

after letting semen ferment on my dick for a week... i finally took a shower

when i rubbed soap on my dick, the covalent bonds created by soap hitting the rotten semen created the most DISGUSTING and THROAT GAGGING EYE WATERING SMELL EVER KNOWN TO MAN

and whats fucked up is that i have to wait another week to smell it again