The lines you have indicated are said of course by Puck as part of our first introduction to the fairy world that runs parallel alongside the real world of Athenian court life. In these lines he is describing to the fairy of Titania how he loves to indulge in merriment and playing pranks on other people to cause laughter and chaos. The kind of language Puck uses reflects this mischevious streak, as the alliteration in the following quote demonstrates:
There is almost a sense in which this is onomatopeia, as the repetition of the "h" sound helps enact the sound of the laughter of the crowd as they watch the old lady being tricked in such a way. Words such as "neeze" and "swear" likewise have the impact of creating the merry mood as Puck cavorts around on stage, delighting in his tricks.