n. 口交，吮吸阴茎

[ noun ]
oral stimulation of the penis
<noun.act>

fellatio \fel*la"ti*o\ (f[e^]l*l[=a]"sh[=e]*[-o];
f[e^]l*l[=a]"t[=e]*[-o]), n.
a form of sexual activity between two persons in which the
penis of one is stimulated by the other's mouth, especially
until orgasm is achieved. It is a form of oral sex. Compare
{cunnilingus}. The act is also called by the slang term {blow
job}.
[PJC]