From comment #2010702: Like all numbers in this picture, it's Japanese number code. 1 = i(chi) 4 = shi/yo 5 = go/ko
So it can be translated as 'iiyo, koi yo' or 'all right, cum!'
Other related numbers that sometimes appear as well: 1919: Saying each number invidually becomes "i ku i ku", which sounds like "cum, cum" 810: Can be split into "8 10", then translated as "ya ju", for Yajuu Senpai 3777: Sa(n) na(na) na(na) na(na) = Sananana 364364: ่ฆใใใ่ฆใใ, said by Miura Daisenpai