This paper explores how the photo and video-sharing app Snapchat mediates memory and intimacy, using focus group data with 18-year-olds. We use Bergson's ideas about duration and Deleuze and Guattari's theories of affect and assemblages to think about how the digital affordances of 'disappearing' Snapchat technology reshape memory and intimacy in youth sexual and relationship cultures. Our findings illustrate that Snapchat offers a temporal fastness and ephemerality -but also forms of fixity through the screenshotting of 'disappearing' snaps. Because judgement from peers cannot take place publicly within the app, offline discussion of Snapchat activity gains significant traction, making interview accounts of Snapchat use highly relevant. Our analysis of discussions of 'Snapchat memory' explores the gendered aspects of performative 'showing off' and sexual scrutiny, considering what happens when snaps do not disappear and how Snap exchanges can be used as relationship currency; for instance exploring how some participant's challenged Snapchat related slut shaming through their uses of humour. Overall we show how Snapchat is mediating youth intimacy, highlighting the reconditioning that occurs between and across the digital world of Snapchat and the physical world of its youth users -evidence of the blurring of online and offline experiences that disrupts digital dualisms. Stories, snaps and screenshots: what is Snapchat?Snapchat is a photo and video messaging app with an unusual temporal structure. Its uniqueness lies in the transience -more specifically, the possible transience -of the images and videos that users share with each other, called 'snaps'. With a lifespan stipulated by the sender of between one and ten seconds, snaps are ostensibly temporary, ephemeral things. The receiver can however choose to screenshot and preserve a snap, imbuing it with a fixity out of the sender's control (the app will inform them that a screenshot has been taken). Snapchat is aware of this potential permanence; screenshotting is laid out as a playful option in the company's Thus Snapchat's distinct temporality and user affordances have unfolded in ways viewed as having specific impacts, risks and possibilities presented by digital culture around gender and sexuality but also age. In this paper we explore how teenagers use Snapchat and how its temporality and ephemerality shape those teenagers' sexual cultures; that is, their networked subjectivities, connections, intimacies and relationalities online and offline. Our discussion seeks to contribute to research on social media networks that is exploring the discursive, affective and material aspects of how the technological affordances mediate relationships, gender and sexuality in new ways (Chambers, 2013;Van Doorn 2011). We specifically wish to contribute some analysis around temporality, duration and memory, drawing on the work of Henri Bergson and Gilles Deleuze to rethink Snapchat mediations of gender and sexual relationality. We focus on how the supposed disappea...