You don't mention the type of songs you would like to take quotes from, but if they are anything than 'pop' songs (in its broadest sense) then I don't think there would be any problem with this. However the music industry is notoriously sensitive to any suggestion of infringement (think of the Robin Thicke/Blurred Lines case
or one of the other cases noted in this article
from Rolling Stone) and is willing to spend vast sums suing other artists for trivial similarities between lyrics or music, or even bass rhythms). And so while the legal position is the same whether you want to quote from the latest Katy Perry song, or a song from the Sound of Music, it is the attitude of the record companes which you need to consider, and whether, in the case of the former, you are prepared to put up with some bullying letters from their lawyers if they feel you have borrowed 'too much' of one of their songs.
The legal basis for what you would like to do is the fair dealing exception in Section 30(1ZA)
of the Copyright Designs and Patents Act 1988 for the purposes of quotation. This is a new exception which the courts have yet to examine in detail so we don't really know where the limitations might lie. However just using a couplet sounds as if it would fall within the fair dealing rules, provided that that is least amount you need for your purpose. As for attribution, this is normally mandatory for all fair dealing use, but this requirement can be relaxed if "this would be impossible for reasons of practicality or otherwise". I am reasonably confident that including a quote within an artwork would fall within this threshold of impracticality. You say that providing a credit for the song may not be possible 'every time', so obviously where it practical, you should do so.
Whether or not you intend to sell your art, and if so, in what quantity, does not have any direct bearing on the copyright position.