The tactile and kinesthetic sensation of pushing a button is usually lost when interacting with modern devices like touchscreens and/or virtual reality platforms. We present FingerFlex, a standalone glove wearable actuating the metacarpophalangeal joint (MCP) of each finger via shape memory alloy (SMA). SMA actuation is subtle, silent, and light, making it ideal for actuation of the fingers which we use to simulate the sensation of pressing a button. For our first study, we evaluated the engineering performance of FingerFlex by altering the current and triggering different levels of stimuli to the user's fingers. We show that users can perceive at least 3 levels of actuation with an accuracy of 73%. For our second study, we found FingerFlex to perform significantly better in terms of input error on a virtual numblock of a keyboard with no significant change in perceived workload.