While browsing, I came across the tag penis_poke, but found that among the relatively small number of images using the tag, there's ambiguity as to what the tag is for (and there is no wiki page to clarify the matter).
Examples of a person poking a penis...
post #2634909 (Perrine H. Clostermann poking a penis with her finger)
post #2464950 (Kashima poking a penis with her finger)
Examples of a person being poked by a penis...
post #2418438 (Akatsuki's cheek being poked by a penis)
post #2156369 (Juno's breast being poked by a penis)
How should this ambiguity be clarified?