Pressed phonation ("rikimi" in Japanese) is a voice quality that carries important paralinguistic information of expressivity in the emotional or attitudinal states of the speaker. Analysis of pressed voice samples extracted from natural conversational speech firstly shows that irregularity in periodicity (such as in vocal fry and harsh voices) is a common but not a strictly determinant feature of pressed voices. Spectral analysis shows that parameters related with spectral slope are effective to identify part of the pressed voice samples, but fail when vowels are nasalized or double-beating occurs within a glottal cycle. Temporal analyses of speech and EGG waveforms indicate that information about the completely closed period can potentially be used for pressed voice identification.