There are 5 SynDI dates available in the After the Incident DLC, which are tracked as squirrels within the game. To trigger a date, you'll need to find a glowing blue metal cylindrical tube, and land your rider near it. You MUST watch the entire date for it to count! They are as follows:
1 - Force Majeure - Continue through the track after about 30 seconds of average speed through, you'll need to land on a ramp in front of you and then reverse a little to find this.
2 - Forgotten Peak - You'll go through the level and reach a small earthquake/avalanche behind you. On the checkpoint directly after it, fall downwards (under the track) and then bail under this area in order to start the date.
3 - Overflow - Continue through the level until you reach a semi-circle obstacle that you need to go over. Instead of going over, you'll want to hook your tire over the edge, bail down and backwards to find a ladder and a small hole. Fall into the hole to start the date.
4 - Storm Chaser - About 15 seconds into the level, go into the barn, go to the bottom area, and reverse.
5 - Static Discharge - (Same as Lightning Rod Part #3) After the "backflip" checkpoint, go forward, up some stairs, and instead of going forward using the short vertical ramp, reverse down the stairs into a small room. From this room, gain a little speed, and bail up and forward to find the last date.