Japanese words for this sort of thing can be lots of fun! The following are some of the most common Japanese terms for "big cock":
デカマラ
dekamara ("huge cock") <
deka- ("very large, huge, enormous") +
mara (slang for "penis")
デカチン
dekachin ("huge penis") <
deka- +
chin (root of
chinchin,
chinpo,
chinko, etc., all of which are common colloquial Japanese words for "penis")
巨根
kyokon ("huge root") < something like an abbreviation of pseudo-Chinese Japanese 巨大
kyodai ("gigantic") + 男根
dankon ("man root," another word for "penis")
太マラ
futomara ("fat cock, thick cock") <
futo- ("fat, thick (as a rod-shaped object; opposite of "slender")") +
mara
Actually, any combination of one of the Japanese roots
deka- ("huge"),
futo- ("fat, thick"), or
naga- ("long") plus one of the Japanese roots
chin ("penis") or
mara (slang for "penis") should work.
Of course, besides the aforementioned compound words, you may also create a Japanese phrase that literally means "a penis that is large," such as 大きなおチンチン
ookina o-chinchin, "a penis that is long," such as 長いチンチン
nagai chinchin, and so forth.
Please be cautious about using any of these words in public or in conversation with anyone with whom you are not very intimate.
