A writing instrument includes a barrel and a cap capable of being assembled with and secured to the barrel. The barrel carries a writing instrument. The cap carries a clip. A free end of the clip includes a detent that can be received by a corresponding indentation of an exterior surface of an external portion of the barrel when the cap is assembled with the barrel. The detent of the clip and the indentation of the barrel are capable of securing the cap and the barrel in their assembled relationship. The writing instrument may be compact. Methods of using a writing instrument include securing a cap of the writing instrument to a barrel of the writing instrument by causing a detent of a free end of a clip of the cap to engage a corresponding indentation of an exterior portion of the barrel.