You would say, "soplarlo hacia fuera tu asno". AnswerParty!
The prepositions of the Spanish language function exclusively as such, therefore, the language does not use postposition constructions. Most derive from Latin, excepting the Arabic-derived hasta (“until”); yet the list herein includes two archaic prepositions — so (“under”) and cabe (“beside”), and excludes vía (“by way of, via”) and pro (“in favour of”), two Latinisms recently integrated to the language. Pedagogically, Spanish language education imparts command of these words via mnemonic-device recitation of: a, ante, bajo, cabe, con, contra, de, desde, durante, en, entre, hacia, hasta, mediante, para, por, según, sin, so, sobre, and tras.
A generally denotes to and at; it has these notable usages: